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T100MD+
Super Programmable Controllers
User’s Manual
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Triangle Research International Pte Ltd of Singapore (“ TRi ”)
and the Buyer agree to the following terms and conditions of
Sale and Purchase:
1. The T100M+ Programmable Controller is guaranteed
against defects in materials or workmanship for a period of
one year from the date of registered purchase. Any unit
which is found to be defective will, at the discretion of TRi,
be repaired or replaced.
2. TRi will not be responsible for the repair or replacement of
any unit damaged by user modification, negligence,
abuse and mishandling, or improper installation.
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respective industry.
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Notes to Buyer: If you disagree with any of the above terms
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Table of Contents
Chapter 1: Special I/Os and Analog Interfacing
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
Introduction
Special Digital I/Os
Stepper Motors Controller Outputs
PWM Outputs
Using High Speed Counter Inputs with Rotary Encoder
Using Interrupt Inputs
Using Pulse Measurement Inputs
Analog I/Os
Serial Communication Ports
1.9.1 COMM1: RS232C with Female DB9
1.9,2 COMM3: Two-wire RS485 Port (& Applications)
1.9.3 Changing Baud Rate and Communication Format:
Use of SETBAUD Statement
1.9.4 Support of Multiple Communication Protocols
1.9.5 Accessing the COMM Ports from within TBASIC
1.9.6 Using Modem to Remotely Program/Monitor PLC
1.9.7 Constructing a 2nd Multi-drop Network
1.10 DIP Switches
1.11 CPU Status Indicators
1.12 Internal Relays, Timers & Counters, etc.
Page
1-1
1-1
1-2
1-4
1-7
1-8
1-9
1-10
1-12
1-12
1-13
1-15
1-16
1-18
1-19
1-21
1-21
1-22
1-23
Chapter 2: Operating Procedure
2.1
2.2
2.3
2.4
2.5
Programming
Simulation
Transferring Program to PLC
Errors and Problems
On-Line Monitoring & Control
2.5.1 Monitoring PLC’s I/O Logic States
2.5.2 Viewing and Modifying PLC’s Internal Variables
2.5.3 Force Setting/Resetting I/O Bits
2.5.4 Suspending PLC’s Ladder Program
2.6 Ladder Monitoring
2.7 Uploading Ladder Program from PLC
2.8 Changing Timers and Counters Set Values
2.9 Setting PLC’s Real Timer Clock
2.10 Trouble-Shooting Communication Error
2-1
2-1
2-1
2-2
2-3
2-3
2-3
2-3
2-4
2-4
2-5
2-6
2-6
2-7
Table of Contents
Chapter 3: Host Communication
3.1
3.2
Point-to-point Communication
Multi-Point Communication System
3.2.1 RS485 Network Interface Hardware
3.2.2 Protection of RS485 Interface
3.2.3 Single Master RS485 Networking Fundamentals
3.2.4 Multi-Masters RS485 Networking Fundamentals
3.2.5 Command/Response Block Format (Multipoint)
3.2.6 Communication Procedure
3-2
3-3
3-3
3-4
3-6
3-7
3-9
3-10
3.3
3.4
Using Network TRiLOGI
Trouble-Shooting RS485 Network
3-11
3-12
Chapter 4: Command/Response Format
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20
4.21
4.22
4.23
4.24
4.25
4.26
4.27
4.28
4.29
Device ID Read
Device ID Write
Read Input Channels
Read Output Channels
Read Relay Channels
Read Timer Contacts
Read Counter Contacts
Read Timer Present Value (P.V.)
Read Timer Set Value (S.V.)
Read Counter Present Values (P.V.)
Read Counter Set Value (S.V.)
Read Variable - Integers (A to Z)
Read Variable - Strings (A$ to Z$)
Read Variable - Data Memory (DM[1] to DM[4000])
Read Variable - System Variables
Read Variable - High Speed Counter HSCPV[ ]
Write Inputs
Write Outputs
Write Relays
Write Timer-Contacts
Write Counter-contacts
Write Timer Present Value (P.V.)
Write Timer Set Value (S.V.)
Write Counter Present Value (P.V.)
Write Counter Set Value (S.V.)
Write Variable - Integers (A to Z)
Write Variable - Strings (A$ to Z$)
Write Variable - Data Memories (DM[1] to DM[4000])
Write Variable - System Variables
4-1
4-1
4-1
4-2
4-3
4-3
4-4
4-4
4-5
4-5
4-6
4-6
4-6
4-6
4-7
4-8
4-8
4-8
4-8
4-9
4-9
4-9
4-10
4-10
4-10
4-11
4-11
4-11
4-12
Table of Contents
4.30
4.31
4.32
4.33
4.34
4.35
4.36
Write Variable - High Speed Counter HSCPV[ ]
Update Real Time Clock Module
Halting the PLC
Resume PLC Operation
Host Communication Program Examples
Inter-Networking Using NETCMD$ command
Inter-Networking Using MODBUS Protocols
4-12
4-12
4-13
4-13
4-14
4-15
4-15
Chapter 5: MODBUS/OMRON Protocols Support
5.1
5.2
5.3
5.4
5.5
MODBUS ASCII Protocol Support
MODBUS RTU Protocol Support
OMRON Host Link Command Support
Appliation Example: Interfacing to SCADA Software
Using The T100M+ PLC as MODBUS Master
5-1
5-3
5-4
5-4
5-5
Chapter 1 Special I/Os and Analog Interfacing
1.1 Introduction
A Standard T100MD+ PLC features the following:
1)
2)
4 to 8 channels of 10-bit Analog Inputs. (4 on T100MD1616+)
1 to 2 channels of 8-bit Analog outputs.
3)
2-channel programmable Motion Controllers for controlling stepper motors up
to 20,000 pulses-per-second.
4)
2-channel Pulse Width Modulated (PWM) outputs.
5)
2-channel 32-bit High Speed Counters (HSC) counts up to 10,000 Hz.
6)
4-channel Interrupt Inputs.
7)
2-channel pulse measurement inputs capable of measuring frequency and
pulse-width of incoming pulses up to 10,000 Hz.
8)
Real time Clock/Calendar for programming multiple scheduled ON/OFF
events.
9)
6016 Words (16-bit) of EEPROM Program Memory.
10) 1700 Words (16-bit) of programmable EEPROM for user’s data.
11) Built-in 16 channels of PID-computation engines let T100MD+ PLCs directly
provide Proportional, Integral and Derivative (PID) type digital control for process
automation.
12) One Independent RS232 port for connection to a host PC for programming or
monitoring.
13) One independent RS485 port for networking or for connecting to external
peripherals such as LCD display and RS485-based analog I/O cards, etc.
14) Industry Standard Protocols: Both RS232 and RS485 serial port simultaneously
support multiple communication protocols, as follow:
i) Native ASCII based Host Link Commands.
ii) MODBUS RTU protocols
iii) MODBUS ASCII Protocols
iv) OMRON C20H Host Link Commands.
v) EMIT 3.0 protocol by emWare Inc.
14) Watch-Dog Timer (WDT) which resets the PLC if the CPU malfunctions due to
hardware or software error. A system reset by WDT can be determined by the
STATUS(1) command.
1.2 Special Digital I/Os
Four of the first 8 ON/OFF inputs of the T100MD+ PLC can be configured as
“special inputs” such as High Speed Counters, Interrupts and Pulse
Measurement. Some of the first 8 outputs can also be configured as PWM
and the stepper controller pulse-outputs. If these special I/Os are not used,
then they can be used as ordinary ON/OFF type I/O in the ladder diagram.
Note that if two special functions share the same I/O then only one of them
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T100MD+ PLCs
Chapter 1 : Installation
can be active at any one time. The location of these special I/O are
tabulated as follows:
Special Inputs
Input #
1
2
3
4
5
6
7
8
High Speed Counter
Ch #1: Phase A
Ch #1: Phase B
Ch #2: Phase A
Ch #2: Phase B
-
Interrupt
Ch #1
Ch #2
Ch #3
Ch #4
-
Pulse Measurement
Ch #1
Ch #2
-
Note: A pin defined as a special input cannot simultaneously act as another
special input. E.g. Pin 3 cannot be used as high speed counter and at
the same time serves as a pulse measuring pin.
Special Outputs
Output #
1
2
3
4
5
6
7
8
Stepper pulse output
Direction for Ch #1
Direction for Ch #2
Ch #1
Ch #2
-
PWM output
Ch #1
Ch #2
These special I/O therefore share the same electrical specifications as the
ON/OFF type I/O, which have already been described in the Installation
Guide.
1.3 Stepper Motors Controller Outputs
Technical Specifications:
No. of Channels
Max. Pulse Rate (pps)
Maximum Load Current
Velocity Profile
(Defined by STEPSPEED)
Maximum number of steps
TBASIC commands
2
20000 (single channel running)
10000 (two channels running)
1A @24V DC
Trapezoidal
-accelerate from 1/8 max pps to max pps.
-decelerate from max pps to 1/8 max pps)
31
9
2 ~ 2 (= 2.1 x 10 )
STEPSPEED, STEPMOVEABS,
STEPCOUNTABS( ), STEPMOVE,
STEPSTOP, STEPCOUNT( )
It is essential to understand the difference between a stepper motor
“Controller” and a stepper motor “Driver”. A stepper motor “Driver” comprises
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T100MD+ PLCs
Chapter 1 : Installation
the power electronics circuitry which provides the voltage, current and
phase rotation to the stepper motor coils.
The T100MD+’s built-in Stepper-Motor Controller, on the other hand, only
generates the required number of "pulses" and sets the direction signal
according to the defined acceleration and maximum pulsing rate
specified by "STEPSPEED" and “STEPMOVE” commands. You cannot directly
connect the "pulses" to the stepper motor. You will need a stepper motor
"driver" which you can buy from the motor vendor. Depending on the power
output, the number of phases of the stepper motor, and whether you need
micro-stepping, the driver can vary in size and cost. Most stepper motor
drivers have opto-isolated inputs which accept a direction signal and
stepping-pulse signal from the "Stepper Motor Controller". In this case the
T100MD is the "Stepper Motor Controller" which will supply the required pulse
and direction-select signals to the driver.
Note that the digital output #1 and #2 automatically become the
direction-select signals for Stepper controller #1 and #2, respectively when
the stepper controllers are being used. The direction pin is turned ON when
the motor moves in the negative direction and turned OFF when the
stepper motor moves in the positive direction. The STEPMOVEABS command
makes it extremely simple to position the motor at an absolute location,
while the STEPMOVE command let you implement incremental move in
either directions for each channel.
Interfacing to 5V Stepper Motor Driver Inputs
Some stepper motor drivers accept only 5V signals from the stepper motor
controller. In such case you need to determine whether the driver’s inputs
are opto-isolated. If they are then you can simply connect a 2.2K current
limiting resistor in series to the path from the PLC’s output to the driver’s
inputs, as shown in the following diagram:
Stepper Motor Driver
Direction Select Input
T100MD1616+ PLC
1
OUTPUTS
R
+V
0V
If
12-24V DC
Power Supply
for PLC
2
Stepping Pulse Input
3
Calculation:
IF = 10mA
4
5
R
If
R = (V - 5)/0.01
e.g. for V=24V,
R = (24-5)/0.01 =1.9K
6
Select R=2K2
Rating = 192/2200
= 0.16W
Use 0.5W resistor.
+24V
GND
PLC’s Power Supply
Figure 1.1
1-3
T100MD+ PLCs
Chapter 1 : Installation
However, if the stepper motor driver input is only 5V CMOS level and non
opto-isolated, then you need to convert the 12-24V outputs to 5V. This can
be achieved using low cost transistor such as a 2N4403. A better way is to
use an opto-isolator with logic level output as shown in Figure 1.2. This
provides a galvanic isolation between the PLC and the stepper motor driver.
+5V 0V (Stepper’s supply)
Logic output
Optoisolator
H11L2
or H11L3
(Quality Technology)
+V
12-24V DC
Power Supply 0V
for PLC
1
OUTPUTS
5
6
5
2
4
6
7
2K2 resistor
(2.2K)
8
To 5V CMOS
stepper driver input
(5mA max)
GND
Figure 1.2 Conversion of T100MD outputs to 5V logic level
1.4 PWM Outputs
Pulse-Width Modulation (PWM) is a highly efficient and convenient way of
controlling output voltage to devices with large time constants, such as
controlling the speed of a DC motor, the power to a heating element or the
position of a proportional valve.
PWM works by first turning the output to full voltage for a short while and then
shutting it off for another short while and then turning it on again and so on
in accurate time intervals. This can be illustrated in the following diagram:
Load
Voltage
a
b
a
Average
voltage = a + b
V Full
x V Full
The average voltage seen by the load is determined by the “duty cycle” of
the PWM wave form. The duty cycle is defined as follow:
a
Duty Cycle =
a+b
x 100%
Period = (a + b)
Frequency = 1/period Hz
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T100MD+ PLCs
Chapter 1 : Installation
Load
Voltage
a
b
a
Average
voltage = a + b
VFull
x VFull
The average voltage seen by the load is determined by the “duty cycle” of
the PWM wave form. The duty cycle is defined as follow:
a
Duty Cycle =
a+b
x 100%
Period = (a + b)
Frequency = 1/period Hz
Average voltage = % duty cycle multiplied by the full load voltage VFull.
Since the voltage applied to the load is either “Fully ON” or “Fully OFF”, it is
highly efficient because the switching transistors are working in their
saturated and cut-off region and dissipate very little power when it is fully
turned ON or OFF.
Technical Specifications:
No. of Channels
Duty Cycle range
Actual Resolution
Available Frequencies (Hz)
Relevant TBASIC commands
2
0.00 to 100.00
0.4%
16, 32, 63, 250, 500, 2000,
8000 and 32000 Hz
setPWM
The frequency of the PWM waveform can also be varied. T100MD+
supports the following frequencies: 16, 32, 63, 250, 500, 2000, 8000 and
32000 Hz. Usually it is better to select as high a frequency as possible
because the resulting effect is smoother for higher frequencies. However,
some systems may not respond properly if the PWM frequency is too high, in
such cases a lower frequency should be selected.
The TBASIC setPWM statement controls the frequency and duty-cycle
settings of the PWM channel. The T100MD+ PLC features two channels of
PWM on its outputs #7 and #8. Since these two outputs are high voltage,
high current outputs (24V, 1A) they can be used to directly control the
speed of a small DC motor of up to maximum of 1A current. They can also
directly drive proportional (variable position) valves whose opening is
dependent on the applied voltage.
Increasing Output Drive Current (Non OptoOpto-Isolated)
If you need to control power devices which demand more than the 1A
1-5
T100MD+ PLCs
Chapter 1 : Installation
maximum limit that output #7 & #8 can drive, you can use the following
circuit to amplify the drive current:
+24V
S
2k2
IRF9530 or IRF9520
(P-channel MOSFET)
G
PLC’s
output 7 or 8
D
2k2
PWM
Load (max
12A @24VDC)
Figure 1.3
The MOSFET driver IRF9530 can drive up to 12A of currents. However, note
that the output has been converted into a “Source” (PNP) type. The above
circuit is also not opto-isolated and hence you have to take the usual
precautions of preventing the large current load demand from interfering
with the power supply voltage of the PLC.
Increasing Output Drive Current (Opto(Opto-Isolated)
The advantage of using PWM is that you can easily amplify the drive current
to a larger load such as a larger permanent magnet DC motor by using a
power transistor or power MOSFET to boost the current switching capability. If
the load is of different voltages and the load current is high, you should use
an opto-isolator to isolate the PLC from the high current load, as illustrated in
Figure 1.4
Flyback Diode
Bridge
Rectifier
4N35
Optoisolator
+V
12-24V DC
Power Supply 0V
for PLC
-
220K
M
+
6
OUTPUTS
5
1
5
2
4
6
~
D
G
R1
7 (PWM1)
8
AC Source
2K2
R2
S
GND
Voltage divider to obtain approx.
10V DC at gate G. For DC48V
load, choose R1 = 3.9K, R2=1K
Figure 1.4
N-channel Power MOSFET
e.g. IRF530 can sink 12A DC
at up to DC100V max.
PWM Speed Control of a large DC Motor.
Note:
1-6
T100MD+ PLCs
Chapter 1 : Installation
a)
The opto-isolator must be able to operate at a frequency matching that
of the PWM frequency, otherwise the resulting output waveform will be
distorted and effective speed control cannot be attained.
b)
The simple PWM speed control scheme described above is open-loop
type and does not regulate the speed with respect to changing load
torque. Closed-loop speed control is attainable if a tachometer (either
digital or analog) is used which feeds back to the CPU the actual
speed. Based on the error between the set point speed and the actual
speed, the software can then adjust the PWM duty cycle accordingly to
offset speed variation caused by the varying load torque. A PID function
may also be invoked to provide sophisticated PID type of speed control.
c)
The T100MD’s PWM can be used to control the speed of small to
medium size motors. For very large motors (above 0.5KW), industrialstrength variable-speed drivers should be used instead.
1.5 Using High Speed Counter Inputs with A Rotary Encoder
Technical Specifications:
No. of Channels
Maximum acceptable pulse rate
Quadrature signal decoding
Relevant TBASIC Commands
2
10KHz for T100MD
4KHz for T100MX
Automatic
HSCDEF, HSCOFF, HSCPV[ ]
Descriptions:
Input #3, 4 and Inputs #5, 6 form two channels of high speed counter
inputs which can interface directly to a rotary encoder that produces
“quadrature” outputs. A quadrature encoder produces two pulse trains at
90o phase shift from each other as follows:
Direction of Rotation
90o
Phase A
Phase B
90o
Direction of Rotation
When the encoder shaft rotates in one direction, phase A leads phase B by
90 degrees. When the shaft rotates in the opposite direction, phase B will
lead phase A by 90 degrees. The quadrature signals therefore provide an
indication of the direction of rotation.
T100MD handles the quadrature signals as follows: if the pulse train arriving
at input #3 leads the pulse train at input #4, the High Speed Counter (HSC)
#1 increments on every pulse. If the pulse train arriving at input #3 lags the
1-7
T100MD+ PLCs
Chapter 1 : Installation
pulse trains at input #4, then the HSC #1 decrements. Note that if input #4
is OFF, then pulse trains arriving at input #3 is considered to lead the input
#4 and HSC #1 will be incremented. Likewise if input #3 is OFF, then pulse
trains arriving at input #4 will decrement HSC #1.
Input #5 and #6 form the inputs for High Speed Counter channel #2 and
they operate in the same way as Input#3 and #4 for HSC#1 described
above.
The fact that the T100MD+ PLC automatically takes care of the direction of
rotation of the quadrature encoder greatly simplifies the programmer’s task
of handling high-speed encoder feedback. The HSCdef statement can be
used to define a CusFn to be executed when the HSC reaches a certain
pre-defined value. Within this CusFn you can define the action to be taken
and define the next CusFn to be executed when the HSC reaches another
value.
Enhanced Quadrature Decoding
The default method in which the PLC handles quadrature signal as
described above is somewhat simplistic. It does not take into consideration
the “jiggling” effect that occurs when the encoder is positioned at the
transition edge of a phase. Mechanical vibration could cause multiple
counts if the rotor shaft “jiggle” at the transition edge of the phase, resulting
in multiple triggering of the counter. This simplistic implementation, however,
does have the advantage that the HSC can also be used for single-phase
high-speed counting.
For M-series PLC with firmware revision of r39 and above, an enhanced
quadrature decoding routine is provided which will lock out multiple
counting by examining the co-relationship between the two phases. You
can configure the M-series PLC to use the enhanced quadrature counting
by using the SETSYSTEM command, as follows:
SETSYTEM 4, n.
n=0 == simple decoding for both HSC1 & HSC2.
n=1 for enhanced quadrature decoding in HSC1 only.
n=2 for enhanced quadrature decoding in HSC2 only
n=3 for enhanced quadrature decoding in both HSC1 & HSC2.
Interfacing to 5V type Quadrature Encoder
If you have a choice, you should select an encoder that can produce 12V
or 24V output pulses so that they can drive the inputs #3,4,5 or 6 directly. If
you have 5V type of encoder only, then you need to add a transistor driver
to interface to the PLC’s inputs. The simplest way is to use an IC driver
ULN2003 connected as shown in Figure 1.5.
1-8
T100MD+ PLCs
Chapter 1 : Installation
+5V
ULN2003A
5V Phase A
1
16
5V Phase B
2
15
Input #3
Input #4
T100MD1616+
Encoder
8
GND
PLC’s 0V terminal
0V
Figure 1.5
Interfacing 5V type Rotary Encoder
1.6 Using Interrupt Inputs
During normal PLC ladder program execution, the CPU scans the entire
ladder program starting from the first element, progressively solving the
logic equation at each circuit until it reaches the last element. After which it
will update the physical Inputs and Outputs (I/O) at the end of the scan.
Hence the location of a logic element within the ladder diagram is
important because of this sequential nature of the program execution.
When scanning the ladder program, the CPU uses some internal memory
variables to represent the logic states of the inputs obtained during the last
I/O refresh cycle. Likewise, any changes to the logic state of the outputs are
temporarily stored in the output memory variable (not the actual output pin)
and will only be updated to the physical output during the next I/O refresh.
You may see that any changes to the input logic state will only be noticed
by the CPU when it has completed the current scan and starts to refresh its
input variables. The input logic state must also persist for at least one scan
time to be recognized by the CPU. In some situations this may not be
desirable because any response to the event will take at least one scan
time or more.
An interrupt input, on the other hand, may occur randomly and the CPU will
have to immediately suspend whatever it is doing and start “servicing” the
interrupt. Hence the CPU responds much faster to an interrupt input. In
addition, interrupts are “edge-triggered”, meaning that the interrupt
condition occurs when the input either changes from ON to OFF or from
OFF to ON. Consequently, the input logic state need not persist for longer
than the logic scan time for it to be recognized by the CPU.
1-9
T100MD+ PLCs
Chapter 1 : Installation
Any one or all of inputs #3 to #7 can be used as interrupt inputs when
defined by the INTDEF statement. The Interrupt inputs may also be defined
as either rising-edge triggered (input goes from OFF to ON) or falling-edge
triggered (input goes from ON to OFF). When the defined edges occur, the
defined CusFn will be immediately executed irrespective of the current state
of execution of the ladder program.
1.7 Using Pulse Measurement Inputs
T100MD PLC provides a very straight forward means to measure the pulse
width or frequency of a square-wave pulse-train arriving at its Pulse
Measurement (PM) inputs #3 or #4.
To use the input to measure pulse width or frequency, execute the PMON
statement to configure the relevant input to become a pulse measurement
input. Thereafter the pulse width (in µs) or the pulse frequency (in Hz) can be
easily obtained from the PULSEWIDTH(n) or PULSEFREQUENCY(n) function.
+24V
NPN type
Optical
Sensor
Input #3
T100MD PLC
Motor
0V
Figure 1.6 Setting Up a Simple Tachometer or Encoder
Applications
1) One useful application of the PM capability is to measure the speed of
rotation of a motor. A simple optical sensor, coupled with a rotating disk
with slots fitted to the shaft of a motor (see Figure 1.6) can be
fabricated economically. When the motor turns, the sensor will generate
a series of pulses. The frequency of this pulse train relates directly to the
rotational speed of the motor and can be used to provide precise
speed control. Note that the above setup can also double as a low
cost position-feedback encoder when used with the high speed
counter, since the number of pulses counted can be used to determine
the displacement.
2) Some transducers incorporate Voltage-Controlled-Oscillator (VCO) type
of outputs which represent the measured quantities in terms of varying
frequency of the output waveform. Such transducers may be used
1-10
T100MD+ PLCs
Chapter 1 : Installation
conveniently by T100MD using the pulse measurement capability.
However, the frequency of such signal must be below 10,000 Hz.
3) For an application that requires measurement of the frequency of a
high-speed counter, you will need to feed the pulse inputs into both
input #3 and Input #5. In this case HSC #2 is used together with PM #1
to count the input pulses as well as measure its frequency. This is
because an input pin that has been defined as High Speed Counter
cannot simultaneously be defined as Pulse measurement pin. If you
execute both the HSCDEF 1 and PMON 1 in the same program, the last
executed command will take precedence.
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1.8 Analog I/Os
A/D Electrical Characteristics
No. of A/D channel
Resolution:
Built-in Sample & Hold
Conversion Time
: 4 to 8 depending on the model.
:10-bit
: Yes.
:10µs per channel.
D/A Electrical Characteristics
No. of A/D channel
: 1 or 2, depending on the model.
Resolution:
: 8-bit
Conversion Time
: 10µs per channel.
Notes:
1) Although the A/D converters’ actual resolutions are only 10-bit and the D/A
converters’ actual resolutions are only 8-bit, T100MD PLCs normalize all the
analog data to 12-bit numbers. Hence you will find that ADC(n) function returns
the value as 0,4,8,12,16....4092 (not 4095 since the least significant two bits are
always zero). Similarly, the D/A converters shift the 12-bit normalized value
applied to it by four bits to the right to convert it into an 8-bit quantity before
applying the value to the DAC hardware. Hence the full scale value of D/A
occur when the actual digital code = 255. When normalized to 12-bit quantities
= 255 x 16 = 4080.
The reason for normalizing all analog data to 12-bit is that in future if new
models of PLCs with higher resolution A/D or D/A converters are introduced, the
user’s PLC program need not be modified since there will not be needs to
change the computational expression when all data are already treated as 12bit full-scale.
ADC(n) value
4092
4088
4084
12
8
4
0
0
1
Input Voltage
AVCC
Figure 1.7 Transfer Function for 10-bit ADC.
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DAC Output
AV CC
255
256
254
256
2
256
1
256
SetDAC value
0
16
32
48
4064 4080
Figure 1.8 Transfer Function for 8-bit DAC.
Interfacing to Industrial Analog Sensors
Real world sensors such as a J- or K-type thermo-couple temperature probe
produce only microvolts of signal voltage in response to temperature
changes. These signals are too weak to be read by the A/D converters and
hence they must be amplified to a higher voltage and current level before
they can be read by the 0-1V or 0-5V range of the Analog inputs. The
amplification stage is known as a Signal Conditioner. A Signal Conditioner
consists of a precision instrumentation amplifier circuit to eliminate common
mode noise that will swamp the weak signal if not handled properly. You can
buy standard ready-made signal conditioners for a J or K type thermocouple
or you can create you own using a highly integrated single-chip IC available
from vendors such as Analog Device Inc (e.g. AD594/AD595) or from Linear
Technology Inc.
The signal conditioners may have their own power supply. When selecting a
signal conditioner, make sure that you select one with output signal in either
0-1V, 0-5V, 0-10V, 0-20mA or 4-20mA ranges to match that available on the
PLC so that the analog data can be read easily.
1.9 Serial Communication Ports
The latest revision (Rev. D or D-1) of the T100MD+ features two independent
serial ports that can simultaneously communicate with other devices using a
variety of protocols. They can also be programmed to accept or send ASCII
or binary data using the TBASIC built-in commands such as INPUT$(n),
INCOMM(n), PRINT #n, OUTCOMM n, d.
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The first serial port (COMM1) is an RS232C port which is compatible with most
PC RS232C ports. The second serial port (COMM3) is a two-wire RS485 port
that allows multiple PLCs to be connected to a single host computer or a
master PLC for networking or to implement a distributed control system.
1.9.1 COMM1: RS232C Port with Female DB9 Connector
This port is configured as a DCE (Data Communication Equipment) and
is designed to connect directly to the PC’s serial port without the need
for a null modem. COMM1 communicates with the host computer at a
default baud rate of 38,400 bit-per-second with 8 data bits, 1 stop bit
and no parity. if DIP switch SW1-4 is set during power-on, COMM1
default baud rate will be changed to 9600 baud. This is the main
communication port for program transfer and on-line monitoring of the
PLC. The pin connections with the host PC are shown below:
Figure 1.9 Connecting COMM1 with PC
However, to connect COMM1 to another DCE device (e.g., a modem),
you need to make a special cable which swaps the transmit and
receive signals, as follow:
T100MD COMM1
(Female DB9)
1
2
3
4
5
6
7
8
9
Special cable
1
2
3
4
5
6
7
8
9
Modem
(Female DB9)
Figure 1.10 Connecting COMM1 to a MODEM
Pin 4 and 6 are handshaking signals whose presence may be required
by some modems to work properly, so these pins are connected as
shown in the diagram.
1.9.2 COMM3: Two-wire RS485 Port
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This half-duplex port is meant for networking or for connecting to
optional peripherals such as a serial LCD/LED message-display unit or
for inter-communication between PLCs. Up to 32 RS232 devices may
be linked together in an RS485 network.
The RS485 port is available on a 2-way screw terminal to the left side of
the power supply terminal (please refer to Installation Guide). For
successful communication using the RS485 port, you need to correctly
connect the ‘+’ and ‘-’ terminals to the RS485 equipment using a
twisted pair cable. If you are using the PC as the network host, you will
need a RS232C-to-RS485 converter. The following describes some
possible uses of the RS485 port.
a) PROGRAMMING AND MONITORING
A T100MD+ PLC can be programmed via its RS485 port on a oneto-one or multi-drop manner. Since most PCs only have RS232
port(s) you need to purchase a RS232-to-RS485 converter in order
to program the PLC via its COMM3 port. Most commonly available
type of RS485 converters in the market today use the RTS signal to
control the RS485 transmitter direction, which is supported by
TRiLOGI Version 4.x and the TLServer software. Auto-turnaround type
may be useable if the turnaround time is less than 0.1ms. Please
check with your dealer or email [email protected] for approved
models of converters that are tested to work with TRiLOGI.
This is particularly useful if COMM1 is already assigned to other tasks
such as interfacing to modem, bar code readers, SCADA system or
MMI, the programmer can continue to program and monitor the
PLC using its RS485 port while its COMM1 is actively communicating
with other devices. This makes it much easier to troubleshoot
communication problems at COMM1 since you can continuously
monitor the data exchange between the PLC and the external
devices connected to its COMM1.
b) CONNECT MANY PLCs TO A ONE TLSERVER: A single PC
running the TLServer program can provide service to all the PLCs
connected to it via RS485 for remote programming, monitoring
and servicing outgoing email requests via the Internet using the
Internet TRiLOGI client. All M and H-series PLCs are installed with the
standard SN75176 driver IC that allows up to 31 PLCs to be
connected to a single PC. However, if you replace the SN75176 IC
with a 1/8 power type, such as the Linear Technology Inc’s
LTC1487, then up to 255 PLCs can be connected to a single PC
running the TLServer.
c) DISTRIBUTED CONTROL: Another important use of the RS485
port will be to connect a T100MD to other T100MD or H-series PLCs.
One T100MD PLC will act as the master and all other PLCs will act
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as slaves. Each PLC must be given a unique ID. The master will
send commands to all the slaves using the “NETCMD” or
READMODBUS or WRITEMODBUS functions and to coordinate
information flow between the PLCs. This allows a big system to be
built by employing multiple units of M or H-series PLCs connected in
a network. This results in more elegant implementation of complex
control systems and simplifies maintenance problems.
d) INTERFACING H-SERIES PLCs TO MODBUS OR INTERNET:
Since the T100MD+ PLC supports MODBUS protocols, a master PLC
can serve as the gateway to interface non MODBUS-enabled PLCs
such as the H-series to third party SCADA software or MMI hardware
that speaks MODBUS. It also allows H-series PLCs to be controlled or
monitored on the Internet via a T100MD+. The master T100MD+ will
use its RS485 port to pull data from the H-series PLC into its datamemory. The data memory in the T100MD PLCs are in turn
accessible by a SCADA program using the MODBUS protocol and
are also accessible from the Internet using the TRiLOGI client/server
software suite.
1.9.3 Changing Baud Rate and Communication Formats: Use of the
SETBAUD Statement
The T100MD+ PLC’s COMM ports are highly configurable. Both COMM
ports can be set to a wide range of baud rates. You can also program
them to communicate in either 7 or 8 data bits, 1 or 2 stop bits, odd,
even or no parity. The baud rate and communication formats of the
serial ports are set by the following command:
SETBAUD ch, baud_no
ch represents the COMM port number (1 or 3 only). The baud_no
parameters takes value from 0 - 255 (&H0 to &HFF) which gives
additional configuration of communication format. The upper 4 bits of
baud_no specify the communication format (number of data bits,
number of stop bits and parity) and the lower 4 bits represent the baud
rate. Hence the baud_no for 8 data bit,1 stop bit and no parity is the
same as the old models, providing compatibility across the family.
Once the new baud rate has been set, it will not be changed until
execution of another SETBAUD statement or when the power is turned
OFF. The baud rate is not affected by software RESET. The available
baud rates and their corresponding baud rate numbers for COMM1
are shown below:
Format
8, 1, n
8, 1, e
baud_no
0000 xxxx
0100 xxxx
Format
8, 2, n
8, 2, e
baud_no
0001 xxxx
0101 xxxx
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8, 1, o
7, 1, n
7, 1, e
7, 1, o
0110 xxxx
1000 xxxx
1100 xxxx
1110 xxxx
8, 2, o
7, 2, n
7, 2, e
7, 2, o
0111 xxxx
1001 xxxx
1101 xxxx
1111 xxxx
Where xxxx represents the baud rate of the comm port, as follow:
xxxx
Baud Rate
0000
2400
0001
2400
0010
4800
0011
9600
xxxx
1000 1001 1010 1011
Baud Rate 100K 250K 500K 110
0100 0101 0110 0111
19200 31250 38400 62500
1100
150
1101
300
1110
600
1111
1200
A table of all the available baud rates and COMM formats is shown in
the following page. The communication format written as 7,2,e means
7 data bits, 2 stop bits and even parity. Likewise, 8,1,n means 8 data
bits, 1 stop bit and no parity. You can use the table to select the baud
number for a certain baud rate and COMM format. Note that the
circuit design of COMM1 limits its physical maximum baud rate to
100kbps, although its UART can work at up to 500K bits per second.
COMM3 can work at the higher baud rate of up to 500K bps.
Baud No Table (All numbers in Hexadecimal: &H00 to &HFF)
Format
8,1,n 8,1,e 8,1,o 7,1,n 7,1,e 7,1,o 8,2,n 8,2,e 8,2,o 7,2,n 7,2,e 7,2,o
Baud
110
0B 4B 6B 8B CB EB 1B 5B 7B 9B DB FB
150
0C 4C 6C 8C CC EC 1C 5C 7C 9C DC FC
300
0D 4D 6D 8D CD ED 1D 5D 7D 9D DD FD
600
0E 4E 6E 8E CE EE 1E 5E 7E 9E DE FE
1200
0F 4F 6F 8F CF EF 1F 5F 7F 9F DF FF
2400
01 41 61 81 C1 E1 11 51 71 91 D1 F1
4800
02 42 62 82 C2 E2 12 52 72 92 D2 F2
9600
03 43 63 83 C3 E3 13 53 73 93 D3 F3
19200
04 44 64 84 C4 E4 14 54 74 94 D4 F4
31250
05 45 65 85 C5 E5 15 55 75 95 D5 F5
38400
06 46 66 86 C6 E6 16 56 76 96 D6 F6
62500
07 47 67 87 C7 E7 17 57 77 97 D7 F7
100K
08 48 68 88 C8 E8 18 58 78 98 D8 F8
250K
09 49 69 89 C9 E9 19 59 79 99 D9 F9
500K
0A 4A 6A 8A CA EA 1A 5A 7A 9A DA FA
E.g. To set baud rate of COMM3 to 19200, 7 data bit, 1 stop bit and
even parity, execute the statement: SETBAUD 3, &HC4
Important: Since the two COMM ports are independent, they can
be set to different format and baud rate from each other. Please
note that if you change the baud rate or communication format to
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something that is different from that set in the TLServer, then both
the TLServer and TRiLOGI will no longer be able to communicate
with the PLC via this COMM port. You will have to either configure
the TLServer’s serial port setting using its “Serial Communication
Setup” routine to match the PLC, or you can cycle the power to the
PLC to reset the COMM port to the default format (38,400, 8,n,1).
If you had used “1st.Scan” contact to activate the SETBAUD
command than you will need to cycle the power to the PLC with
DIP switch #4 set to ON to halt the execution of the SETBAUD
command. (Also remember that when the PLC is reset this way, its
COMM1 will power up at 9600 bps only so you will need to
temporarily configure TLServer’s serial port to 9600bps to
communicate with it.)
If you need to re-access the port using TRiLOGI, then you will need to
reset the PLC with DIP switch #4 set to ON so that the program will not
execute a SETBAUD command.
1.9.4 Support of Multiple Communication Protocols
The T100MD+ PLC is a real communication wizard! It has been
designed to understand and speak many different types of
communication protocols, some of which are extremely widely used
de facto industry standard, as follows:
a) NATIVE HOST LINK COMMAND
b) MODBUS ASCII (Trademark of Groupe Schneider )
c) MODBUS RTU* (Trademark of Groupe Schneider )
d) OMRON C20H protocols. (Trademark of Omron Corp of Japan)
e) EMIT 3.0 Protocol (Trademark of emWare, Inc)
The command and response formats of the “NATIVE” protocols are
described in details in Chapter 3 & 4. The other protocols and their
address mapping to T100MD+ are described in Chapter 5 & 6. The
two independent COMM ports 1 & 3 support all the above protocols.
Each COMM port can communicate using the same or different
protocols independent of the other. The most wonderful feature of
T100MD+ is that the support of all the above-mentioned protocols
can be fully automatic and totally transparent to the users. There is no
DIP switch to set and no special configuration software to run to
configure the port for a specific communication protocols. The
following describes how the automatic protocol recognition scheme
works:
1) When the PLC is powered ON, both COMM ports are set to the
“AUTO” mode, which means that they are open-minded and listen
to all serial data coming through the COMM ports. The CPU tries to
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determine if the serial data conforms to a certain protocol and if
so, the COMM mode is determined automatically.
2) Once the protocol is recognized, the CPU sets that COMM port to a
specific COMM mode which enables it to process and respond
only to commands that conform to that protocol. Error detection
data such as the “FCS”, “LRC” or CRC are computed accordingly
which are used to verify the integrity of the received commands. If
errors are detected in the command the CPU responds in
accordance with the action specified in the respective protocols.
3) When the COMM port enters a specific COMM mode, it will regard
commands of other protocol as errors and will not accept them.
Hence for example if COMM #1 has received a valid MODBUS RTU
command which puts it in a “RTU” mode, it will no longer respond
to TRiLOGI’s attempts to communicate with it using the “NATIVE”
mode. You will receive a communication error if you try to use
TRiLOGI to access a PLC COMM port that has just been
communicating in other protocol modes.
4) To improve the flexibility of switching from one COMM mode to
another, The T100MD+ incorporates a COMM mode self-reset timer
such that a specific COMM mode will time out automatically and
enters into “AUTO” mode after 10 seconds if no more commands
are received from that COMM port. When a user wants to switch
from one COMM mode to another he/she often will be changing
the serial connector from one device to another. During this time
there is no data received by the COMM port which presents an
opportunity for it to reset its COMM mode. However, the surest way
to reset the specific COMM mode is to cycle the power to the PLC
so that its COMM port will be reset to “AUTO” mode and ready to
communicate with any supported protocols.
5) You can also use the SETPROTOCOL command to set the COMM
port to NO PROTOCOL if you wish to use the COMM port for serial
data input only. This can prevent the PLC from erroneously treating
some serial data as the header of an incoming communication
protocol and respond to it automatically.
SETPROTOCOL can also be used to set the PLC to a specific
protocol. This may be desirable if the COMM port has a specific
role and you do not want it to enter other modes by mistake.
Please refer to the TBASIC Programmer’s Reference manual for
detailed description of the SETPROTOCOL command.
Note: if you fix a COMM port to a non-native, non-auto mode
TRiLOGI will not be able to communicate with the PLC anymore.
You may have to power-cycle the PLC to reset the COMM mode. If
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you use “1st.Scan” contact to activate the SETPROTOCOL
command than you will need to cycle the power to the PLC with
DIP switch #4 set to ON to halt the execution of the SETPROTOCOL
command. (Also remember that when the PLC is reset this way, its
COMM1 will power up at 9600 bps only so you will need to
temporarily configure TLServer’s serial port to 9600bps to
communicate with it.)
1.9.5 Accessing the COMM Ports from within TBASIC (Rev D boards)
Besides responding automatically to specific communication
protocols described in section 1.9.4, both the serial ports COMM #1
and #3 are fully accessible by the user program using the TBASIC
commands: INPUT$, INCOMM, PRINT # and OUTCOMM. It is necessary
to understand how these commands interact with the operating
system, as follows:
When serial data are received by a COMM port, the operating system
of T100MD+ automatically stores them into a 256 bytes circular buffer
so that they can be retrieved by user programs later. The serial data
are buffered even if they are incoming commands of one of the
supported protocols (except EMIT 3.0) described in section 1.9.4. In
addition, processing of a recognized protocol command does not
remove the characters from the serial buffer queue so these data are
still visible to the user’s program.
Each COMM port has its own separate 256-byte serial-in buffer. As
long as the user-program retrieves the data before the 256-byte buffer
is filled up, no data will be lost. If more than 256 bytes have been
stored the buffer wraps around and the oldest data is overwritten first
and so on. The following describes how INCOMM and INPUT$, PRINT #
and OUTCOMM functions interact with the serial buffer:
a) INCOMM (n)
Every execution of the INCOMM(n) function removes one character
from the circular buffer. When no more data is available in the
buffer this function returns a -1. The data removed by INCOMM will
no longer be available for the INPUT$ command.
b) INPUT$(n)
When the INPUT$(n) function is executed, the CPU checks the
COMM #n buffer to see if there is a byte with the value 13 (the
ASCII CR character) which acts as a terminator for the string. If a
string is present, all the characters that make up the string will be
removed from the COMM buffer. If a completed string is not
present then the COMM buffer will not be affected and INPUT$(n)
returns a null string. This ensures that before a complete string is
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received the serial characters will not be lost because of the
unsuccessful execution of the INPUT$(n) function.
c) PRINT #n
The PRINT statement transfers its entire argument to a 256 byte
serial-out buffer which is separate from the serial-in buffer. The
PRINT statement therefore does not affect the content of the serial
buffer for incoming characters. The operating system handles the
actual transfer of each byte of data out of the serial-out buffer in a
timely manner. Again each COMM port has its own independent,
256-byte serial-out buffer and hence the two serial ports can
operate totally independent of each other.
Note that the PLC automatically enables the RS485 transmit driver
when it sends serial characters out of its COMM3 port. When the
stop bit of the last character in the serial-out buffer has been sent
out, the operating system immediately disables the RS485 driver
and enables the receiver. This greatly eases the use of the RS485
port since there is no need for user to bother with the often critical
timing of controlling the RS485 driver/receiver direction.
d) OUTCOMM
This command sends only a single byte out of the serial COMM port
without going through the serial out buffer. For COMM3, it enables
the RS485 transmitter before sending the character and disables it
immediately after the stop bit has been sent out.
1.9.6 Using Modem to Remotely Program/Monitor T100MD+ PLC
TRiLOGI Version 4.1x supports remote dial up to T100MD+ PLC via
standard, off-the-shelf modems. Two modems are involved for any
communication between two devices. The host end of the modem
setup and configuration is handled by TRiLOGI Version 4.1x software,
whereas on the PLC side the PLC has to configure the modem so that
it can successfully communicate with the host computer running
TRiLOGI.
a) Wiring
The modem is often connected to the PLC’s COMM1. Since the
serial port on most modems are DCE type, you will need a make a
special (also known as null-modem) cable to connect them as
shown in figure 1.10. If the modem only has a DB25 connector you
can connect the wires as shown in the following diagram:
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1
T100MD COMM1
(Female DB9)
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
Modem
(Female DB25)
20
Figure 1.11 Connecting COMM1 to a modem’s DB25 port
Note that pin 6 (DSR) and pin 20 (DTR) at the modem end are tied
together. This is often required to inform the modem that the
device is ready for operation so that the modem can work
properly.
A modem may also be connected to COMM3 for multi-drop
remote programming and monitoring using NETWORK TRiLOGI!
However, you will require a special auto-turnaround RS232-to-RS485
converter. Please check with your dealer or email [email protected]
for approved models of such converter.
b) Programming
Since the PLC COMM port does not employ handshaking signals of
the modem’s RS232 port, the maximum baud rate for modem
communication should be restricted to 9600bps or lower for
reliable, continuous communication. In addition, the PLC’s modem
should be configured to auto-answer mode so that automatic
connection is possible when TRiLOGI dials up the modem at the
remote site.
The following TBASIC statements set the COMM port #1 to 9600bps
and put the modem into auto-answer mode:
SETBAUD
1, 3
‘Set to 9600bps, 8 data bits,
‘1 stop bit, no parity.
PRINT #1 “ATDTS0=1”
It is assumed that TRiLOGI would have set the calling modem to
meet the other requirements for “No compression”, “Disable Flow
Control” etc. as described in the TBASIC 4.1 Reference page II.1-4).
As long as one side of the modem is set to those conditions the
other modem will follow during their negotiation phase before
connection. Hence there is no need to send additional AT
commands to set the modem into the above-mentioned modes.
However, if the modem is to be used with other programs (such as
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third party SCADA software) you will need to configure the modem
to meet those other conditions. Please see the application notes
“MODEM-1.ZIP” on your TRiLOGI distribution diskette for details.
Most modems have the ability of storing the configured mode into
their non-volatile memory so that when the modem is next
powered up it will automatically be set in that mode. If you
configure the modem this way there is no need even for the PLC to
initialize the modem at all (though it will still need to set its COMM1’s
baud rate to 9600). The AT commands to achieve this for 100%
Hayes compatible modems are “AT&W0&Y0”. You may check the
modem reference manual for the actual commands for other
makes of modems.
1.9.7 Constructing a 2nd Multi-drop Network
For complex distributed applications, the built-in RS485 port may be
required for internal networking between PLCs for data exchange. Yet
some or all the PLCs may need to be connected to a SCADA system
or MMI. It is possible to construct a second multi-drop network around
the PLC COMM port #1. However, this will require a 4-wire RS485 or
RS422 construction since the PLC COMM port #1 does not have builtin signal to enable/disable the transmitter and receiver of an RS485
driver IC. It is required that each PLC has an RS232-to-4-wire
conversion interface so that they can be connected by a four-wire
RS485/RS422 network to the SCADA host system. Of course there must
also be a 4-wire RS485/RS422 converter at the host computer. The two
COMM ports capability of the T100MD+ (Rev D) can be used to their
fullest extent in such a situation. Please consult your local supplier or
email to: [email protected] for questions regarding such applications.
1.10 DIP SWITCHES
DIP Switch
OFF
ON
SW1-1
All outputs, relays,
timers and counter
values are nonretentive.
Without MX-RTC module - no effect.
If MX-RTC module has been installed, then all the
I/Os, timers and counters as well as all internal
variables retain their value after power off in the
battery-backed RAM. DAC, PWM data will not be
retained, however.
SW1-2
COMM1 responds to COMM3 responds to EMIT 3.0 protocol.
EMIT 3.0 protocol
-
SW1-3
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SW1-4
Chapter 1 : Installation
Normal Run mode
Suspends execution of ladder logic program. But
host communication remains active (e.g. when
used as a slave I/O card only). When power-on with
this switch closed, default baud rate for COMM1 =
9600 bps instead of 38,400 bps.
Note: Although the two independent COMM ports of T100MD+ Rev D PLC
can process NATIVE, MODBUS and OMRON protocols simultaneously, only
either one of the COMM ports may be used for EMIT3.0 protocol, which is
selectable by DIP Switch SW1-2.
Usefulness of SW1-4
We have taken every effort to ensure that the host communication is always
available even when the user-program ends up in a dead-loop. This allows
the user to re-transfer a new program to the PLC and overwrite the bad
program. However, you may still encounter a situation whereby after
transferring a new program to the PLC, you keep encountering
communication error and could not erase the bad program. This is
especially common if you are playing with the communication commands
such as SETBAUD, SETPROTOCOL, PRINT or OUTCOMM which may modify
the communication baud rate, communication format or protocol or
sending data out of a COMM port that conflicts with TRiLOGI. In such cases
you can turn ON DIP Switch SW1-4 and perform a power-on reset for the
PLC. The PLC will not execute the bad program that causes communication
problem and you can then transfer a new program into the PLC to clear up
the problem.
Note that when the PLC is power-reset with DIP Switch #4 set to ON, it’s
default baud rate and communication format for COMM1 becomes 9600,
8,n,1 (COMM3 is not affected). TRiLOGI Version 4.1x is able to automatically
recognize this baud rate. TLServer on the other hand, will not change its
baud rate setting automatically to match the PLC. You will need to
manually change the TLServer’s serial port settings to 9600,n,8,1, in order to
communicate with the PLC after a power-reset with DIP Switch #4 set to ON.
(Remember to switch back to 38,400 after you have cleared the offending
PLC program, otherwise if the PLC is again power-reset with DIP Switch #4
turned OFF, you will face problem communicating with it again because
this time it would assume a baud rate of 38,400!!).
1.11 CPU Status Indicators
There are three LED indicators on T100MD with the following markings:
RTC Pause Run
Error
Error
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Chapter 1 : Installation
All three indicators will be lighted up during power-on when the CPU loads the
PLC program from EEPROM. Thereafter they should go off and if any one of
them remains lighted it represents the various operating status of the PLC as
follow:
a) RTC Error (Green LED)
This indicator will be turned ON after a power-ON or WDT reset unless an
optional battery-backed MX-RTC module has been installed. This
indicates that the real-time clock (RTC) has been reset to some factory’s
pre-set date and time. The RTC.Err flag in the “Special Bit” menu will also
be turned ON. This indicator will be turned OFF automatically after you
have set the PLC’s date and time using the “Set PLC Clock /Calendar”
command in the “Controller” pull-down menu.
b) Pause (Red LED)
This indicator will be turned ON if one of the following occurred:
i) PLC’s EEPROM is corrupted.
ii) A PAUSE statement has been executed
iii) The user halts the PLC by pressing the <P> key during On-Line
Monitoring.
iv) DIP-Switch SW1-4 is turned ON which halts the program.
If this light is ON, please connect the host computer running TRiLOGI
Version 4 to the PLC and run the “On-Line Monitoring” program. You will
be informed of the reason that caused the PAUSE condition. Except for
condition i) and iv), you can release the PLC from the PAUSE state by
pressing the <P> key during “On-Line Monitoring”. If the PLC’s EEPROM is
corrupted then you must re-transfer your program to the PLC again.
c) Run Error (Red LED)
When this indicator turns ON it shows that a run-time error had occurred
during execution of a TBASIC command. The system will halt at the CusFn
where the error took place. If the programmer now executes the “On-Line
Monitoring” command in TRiLOGI, the cause of the run-time error and the
CusFn where the error occurred will be reported on TRiLOGI screen.
TBASIC simulator captures many possible run-time errors including out-ofrange values, but in T100MD PLC only a few most important run-time
errors are reported. The remaining are ignored. The following are the few
run-time errors that will be reported in T100MD:
I)
ii)
iii)
iv)
Divide By Zero
FOR-NEXT loop with STEP = 0!
Call Stack Overflow! Circular CALL suspected!
Illegal Opcode - Please inform manufacturer!
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T100MD+ PLCs
Chapter 1 : Installation
v) System Variable Index out-of-range: This is normally caused by
using an unavailable subscript. E.g. DM[0], INPUT[-1], DM[5000], etc.
Check the subscript value especially if it contains a variable (e.g.
DM[X], if X=0 this will lead to a runtime error).
All run-time errors should be identified and corrected before proceeding
any further.
1.12 Internal Relays, Timers & Counters, etc.
T100MD+ PLC supports up to 256 internal relays, 64 timers (any one or all
can be configured as “High Speed” timers), 64 counters, 8 clock sources of
various periods: 0.01s, 0.02s, 0.05s, 0.1s, 0.2s, 0.5s, 1 sec and 1 minute.
T100MD+ also supports 8 sequencers of 32 steps each.. A sequencer is a
highly convenient feature for programming machines or processes which
operate in fixed sequences. Any one or all of the first 8 counters can be
used as step counters for the sequencers which correspond to sequencers
"Seq1" to "Seq8". Each step of the sequencer (up to 31) can be used as a
contact to the ladder diagram as "SeqN:XX" where N = sequencers # 1 to
8. XX = Step # 0 - 31. Please refer to TRiLOGI Programmer’s Reference Part
I for detailed descriptions of the built-in sequencers.
1-26
Chapter 2 Operating Procedure
2.1 Programming
The T100MD+ controller is programmed using the software TRiLOGI
Version 4.X which runs on an IBM compatible PC, or using or Internet
TRiLOGI 5.0 which runs on multiple platforms. This is a full-screen ladder
logic editor, compiler and simulator software. TRiLOGI Version 4.x is a
standalone DOS based software package which provides a powerful
programming and debugging environment for programming in both
ladder logic and TBASIC. Please refer to the TRiLOGI Programmer’s
Manual for details.
With the introduction of the Internet TRiLOGI 5.0 Client/Server software
suite, the M-series PLC has become the world’s first PLC that is
programmable via the Internet using only a Web-browser. Please refer to
the Internet TRiLOGI Version 5.x on-line helps for detail description of the
installation and operation of this incredibly powerful software.
2.2 Simulation
A great feature unique to the TRiLOGI development environment is the
built-in simulator. With the simulator, you can interact with your program
by simulating the input conditions using only a keyboard and examine
the status and present values of the outputs, relays, timers and counters
on screen immediately. Most Custom functions written in TBASIC can
also be simulated and all the variables can be examined readily on the
simulator screen.
The simulator does not require any physical connection to the target
PLC, and thus offers the most effective way of testing and debugging
your ladder logic program prior to the installation of the hardware.
Programming and debugging time can be greatly reduced if you make
good use of the simulator feature to eliminate as many logic errors as
possible before testing the program on the actual hardware. It also
helps to reduce the chances of costly damage to the machine due to
programming errors.
2.3 Transferring Program to the PLC
Once you are satisfied with the TRiLOGI-simulated scenarios, return to the
ladder logic editor by pressing the <ESC> key. To transfer the ladder
program to T100MD, first connect the PC to COMM1 of the PLC and
then turn on its power supply. You may press <Ctrl-T> on the keyboard
or open the "Controller" pull-down menu and select item "Program
Transfer". TRiLOGI will query the target controller to obtain its maximum
2-1
T100MD+ PLC
Chapter 2 : Operating Procedure
number of inputs, outputs, etc. TRiLOGI will recompile the ladder
program to ensure that these limits are not violated. When compilation is
successful, the compiled code will be transferred to the T100MD PLC in
within seconds.
After the program has been successfully transferred, you will be
prompted to indicate if you wish to clear all outputs, relays, timers,
counters and all the internal system variables to "OFF". A program that is
successfully transferred will be executed at once. If you do not want the
program to execute immediately, you may turn ON DIP switch SW1-4
before transferring the program, and then turn it OFF when you want the
program to run.
If errors occur during program downloading and communication is
aborted, the CPU will not execute the partially transmitted program to
forestall undesirable consequences. If everything goes well, you may
return to the editor by pressing any key.
Password Security
The users may define a Transfer protection password of between 1 to 6
characters by selecting the "Set Password" item from the "Target Access"
menu. Once a password has been defined, you will be prompted to
enter the password whenever you want to transfer a program to the PLC.
Program transfer will be aborted if incorrect password is entered. This is to
prevent alteration of the PLC program by unauthorized personnel.
If you have forgotten the password, then the only way to re-program the
PLC is to first delete the password using the “Delete Password and Clear
Program” command in the “Target Access” menu. The program in the
PLC will be deleted when this command is executed. You have to
download the new program into the PLC for it to operate.
* The password security against unauthorized programming is not supported
on Internet TRiLOGI Version 5.0. There are already two levels of password
structure on Internet TRiLOGI – one is defined on the TLServer and the other
is defined by executing the SETPASSWORD TBASIC command. We feel that
adding one more password layer to the whole PLC programming
environment will only serve to confuse the users. We have thus decided to
omit this from the Internet TRiLOGI Version 5.x. However, if you attempt to
use Version 5.0 to transfer program to a PLC previously protected by
TL41.EXE, TRiLOGI Version 5.0 will still prompt you for a “Prog. Transfer
password”. You will need to enter the authenticated password in order to
proceed any further. In other words, you can still use TL41.EXE to manage
(define or delete ) the Transfer Protection password for the PLC.
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T100MD+ PLC
Chapter 2 : Operating Procedure
2.4 Errors and Problems
Any error in the source file detected during compilation will abort the
program transfer process immediately. The cause of the first error will be
reported on screen, although you should never encounter this problem if
you had simulated the program successfully in TRiLOGI. This is because
TRiLOGI's ease of programming reduces the possibility of errors to a
minimum, and any error would have been detected and rectified
before any simulation can take place.
PLC Program length is measured in (16-bit) “words”. Up to 6016 words
may be programmed into a T100MD+ PLC. If your ladder logic program
exceeds 6016 words after compilation, the compiler will record this as
an error and the downloading process will be aborted. If this happens,
you need to simplify your program to optimize the use of program
memory.
2.5 On-Line Monitoring & Control
TRiLOGI allows direct control of the PLC operation from within the
program. You can enter this mode by selecting the "On-Line
Mon/Control" command from the "Controller" main menu, or by pressing
the "Ctrl-M" hot-key. An "On-Line Monitoring & Control" screen will
appear. The following are what may be done in this mode:
2.5.1 Monitoring PLC’s I/O Logic States
TRiLOGI continuously monitors the I/O logic states and present
values of the timers and counters of the controller and displays
them on screen. You may scroll up and down any I/O window
using the cursor keys and the <PgUp> and <PgDn> keys to
examine I/Os that are outside the present page. A highlight bar
will appear when an I/O window is selected (its border is
highlighted). The location of this highlight bar indicates the
particular I/O bit selected.
selected
2.5.2 Viewing and Modifying PLC’s Internal Variables
If you press the <V> key while you are within the “On-Line
Monitoring & Control” screen, a “View Special Variables” window
will be opened. You can examine the values of all the 26 integer
variables A to Z, string variables A$ to Z$, Data Memory DM[1] to
DM[4000] and other special internal variables such as ADC, DAC,
PWM and the Real-Time-Clock. The values displayed in this
window reflect the actual values of these variables in real time.
The numbers are displayed in decimal form, but if you press the
<H> key it will change into hexadecimal form. Pressing the <D>
key will change it back to decimal mode.
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T100MD+ PLC
Chapter 2 : Operating Procedure
You can also examine the values of other system variables such
INPUT[ ], OUTPUT[ ], EMINT[ ] etc. by pressing the <S> key (as for
“Show”) and entering the variable names. If you wish to modify
the content of any variable, simply press the <E> key (as for
“Edit”) and you can enter the variable name followed by the “=“
sign and the value. The entered value for the variable will be
immediately updated into the PLC.
* Note: The “Show” command and the <S> keys are not
supported in Internet TRiLOGI Version 5.x, this is because in
Version 5.x all the system variable data are already listed on the
fourth screen of the “View Variable” window.
2.5.3
2.5.3 Force Setting/Resetting I/O Bits
If you hit the <Enter> key during On-Line Monitoring mode, the
selected I/O bit of the controller will be forced to toggle (change
state) by TRiLOGI using host link commands. If the selected bit is a
physical input bit or has been assigned to an output coil
controlled by the ladder diagram, it will only be toggled for onescan time. After that the controller will refresh its input/output
according to the actual states of the physical inputs and outputs
determined by the outcome of the ladder program. This is
sometimes useful during program testing or debugging for
temporarily overriding an I/O that does not respond as predicted.
* Note: On Internet TRiLOGI Version 5 you force an I/O by moving
the mouse pointer to the I/O and then click on the left or right
mouse button. See the Internet TRiLOGI on-line helps for more
details.
2.5.4 Suspending PLC's Ladder Program
You can suspend the operation of the controller at any time by
pressing the <P> key (or by clicking the [Pause] button in Internet
TRiLOGI Version 5.x). A warning message will appear and a
flashing sign "System Paused" will be displayed on the upper right
hand corner. When the controller is suspended, its program will
not be executed until it is resumed by pressing the <P> key
again. At this time you can force set or reset any relay or output
bits. This is convenient during programming or debugging as you
can control the output driver to bring any physical component to
any desired locations effortlessly.
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T100MD+ PLC
Chapter 2 : Operating Procedure
2.6 Ladder Monitoring
You can also monitor the logic states of I/Os directly on the ladder
diagram by selecting the "Ladder Monitoring" commands in the
"Controller” or by pressing <Ctrl-L>. When you enter the "Ladder
Monitoring" mode, TRiLOGI will continuously monitor the controller's I/O
logic states and display any "ON" I/O bit with highlighted label names on
the ladder diagram. You can still scroll up/down the ladder programs
while performing ladder monitoring, using the cursor keys, <PgUp>
<PgDn> and <Ctrl-PgUp> and <Ctrl-PgDn>, etc. However, you may
not use the left/right cursor keys to observe logic states of I/Os outside the
current screen.
* Note: In Internet TRiLOGI Version 5.x, ladder monitoring is already part
of the on-line monitoring and hence this is not available as a
stand-alone command.
On-Line Mon/Control and Ladder Monitoring actions are achieved by
continuously sending host link commands to the PLC and analyzing the
response strings immediately in order to update the I/O tables. Since the
controller must spare some time to process the host-link commands, the
overall scan time will slow down during on-line or ladder monitoring.
Take precaution that programs which require fast scan-time, such as
counters fed by the 0.01s and 0.02s clock sources, may lose some
accuracy. Inputs based on interrupts such as High Speed Counters
however will not be affected.
2.7 Uploading Ladder Program from the PLC
(This is not supported on Version 5.0)
TRiLOGI Version 4.X permits you to retrieve the compiled code from the
PLC's EEPROM and re-construct them into ladder circuits. However,
compiled TBASIC-based custom functions cannot be retrieved. (Note
that Internet TRiLOGI Version 5.0 does not support uploading of Ladder
Program from the PLC at all. The uploading function might be made
available in future as a stand-alone utility program).
To perform uploading, open the "Controller" pull down menu and select
the new item "Target Access". A pop-up menu with two items "Set
Password" and "Retrieve PLC's Ladder" will appear. Select "Retrieve PLC's
Ladder" and you will be prompted to confirm your wish to obtain the
ladder program from the PLC.
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T100MD+ PLC
Chapter 2 : Operating Procedure
Note that since the I/O label names and comments defined in the
original program were never saved in the PLC, the re-constructed ladder
diagram can only make use of the I/O labels defined in the currently
opened file. Since the uploaded program replaces all the existing
ladder circuits, make sure that you keep a backup copy if you do not
wish to lose the contents of the currently opened file.
If an I/O referred to by the PLC's program code is not defined in the
current file, the program will prompt you to enter the label name. You
can use the default name by pressing the <ESC> key. A default name
defines an input as "In1", "In2"..., output as "Out1", "Out2"... etc.
Password Security
The users may define a password of 1 to 6 characters by selecting the
"Set Password" item from the "Target Access" menu. Once defined, the
target PLC program may not be uploaded unless the same password is
entered.
If you wish to change the password, select the "Set Password" item and
you will be prompted to enter the original password. If the correct
password is entered, you will be prompted again to enter the new
password. If you simply press the <Enter> key at this time without
entering any character, the original password will be cleared and the
user may freely upload the PLC code.
Once you have entered a password, it will stay with the PLC until you
change it or delete it using the “Delete Password & Clear Program”
command. If you delete the password, the program will be erased as
well. This effectively protects the code from being read by unauthorized
parties.
2.8 Changing Timer and Counter Set Values
In TRiLOGI Version 4.X, timer and counter Set Values (SV) defined in their
respective definition tables can be stored into the PLC using the
command “1: Host Timer/Ctr SV --> PLC” under the “Controller” menu.
Similarly, the PLC’s internal timer and counter SVs can be read into
TRiLOGI by means of the “2: PLC’s Timer/Ctr SV -> Host” command.
Updating of the Set Values is performed without the need to transfer the
entire ladder program. Since timer and counter SVs are often changed
during field-testing, this makes it much quicker to alter such values for
longer ladder programs. It often takes much longer time to transfer the
entire ladder program than just changing a few timer or counter set
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T100MD+ PLC
Chapter 2 : Operating Procedure
values. (Note: this command is not available on Internet TRiLOGI Version
5.0. It may be made available in future as a stand-alone utility
program.)
2.9 Setting PLC’s Real Time Clock
This command lets you set the time and date of the PLC’s built-in Real
Timer Clock (RTC). When you execute this command, It will let you
choose whether you wish to update the PLC’s real-time clock using your
PC’s current date and time, or to enter the data manually.
If you select “Manual Entry”, the program will show you the current date
and time of the PLC in different fields and you can use the normal
editing keys to modify the values. When you press <Enter> key the new
value will be written into the PLC’s RTC. The special bit “RTC.Err” will be
turned OFF after you have executed this command.
MXMX-RTC Module
When the PLC power is turned off, the built-in RTC will stop operating and
the date and time setting will be lost. When the power is re-applied to
the PLC, the RTC must be reset to some factory pre-determined date
and time values. In order to maintain the clock settings (non-volatility),
you can purchase the T100MD+ PLC with the MX-RTC option. The MXRTC module is a special socket attached to the T100MD’s data RAM and
provides a Lithium battery-backed real time clock that continues to run
even when the PLC power is turned off. The “Set PLC’s Clock/Calendar”
command will also set the date and time within the MX-RTC module if
installed.
The MX-RTC module also maintains the contents of all the I/Os and
internal variables stored in the PLC’s data RAM in the event of power lost.
The DIP-switch SW1-1 can be set to avoid clearing of the variables when
power on (please refer to section 1.10 for details). This may be useful for
control systems that must maintain the contents of all data in the event
of a power failure.
2.10 Trouble-Shooting Communication Errors
If you keep encountering the "Communication Error" message when you
execute any command under the “Controller” menu, the following are
some possible causes:
1) The T100MD is not connected to the cable.
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T100MD+ PLC
Chapter 2 : Operating Procedure
2) The host computer COM port is not connected to the cable.
3) Wrong COM port number is specified for the PC. Try another one.
4) Power to PLC is not turned on or an inadequate power supply has
been used. Make sure that the CPU power supply is within
specifications. Try another power supply.
5) Faulty serial port of host computer. Try another computer with a
good working COM port.
6) Faulty serial cable. Try another cable.
7) Faulty PLC. Return the unit to authorized dealer for servicing.
Communication Errors After Transferring A User Program
If you have been able to communicate with the PLC, but all a sudden,
after transferring a new TRiLOGI program into the PLC you keep
encountering the "Communication Error" messages, then the most likely
causes are:
1) Your program has changed the serial port setting to other than 8
data bit, 1 stop bit and no parity. Or you have set the baud rate to
less than 2400 or greater than 38400 bps.
2) You are executing PRINT #, OUTCOMM, NETCMD$, READMODBUS, or
WRITEMODBUS on the same COMM port which TRiLOGI connects to.
TRiLOGI reports a comm error when it receives data that is different
from the expected response from the slave.
To fix the above situation, turn ON DIP Switch SW1-4 and reset the PLC. If
you are able to communicate with the PLC then the problem must
definitely be caused by some offending codes in your TRiLOGI program.
Correct the error and re-transfer the program before turning OFF DIP
SW1-4.
2-8
Chapter 3 Host Communication
While a T100MD+ or T100MX+ PLC is running, a host computer or another
T100M+ PLC (this abbreviation is used to refer to both the T100MD+ and
T100MX+ in the rest of this manual) may send ASCII string commands to it
to read or write to its inputs, outputs, relays, timers, counters and all the
internal variables. These ASCII commands are known as the "host-link
commands" and are to be serially transmitted (via RS232C or RS485 port) to
and from the controller. The default serial port settings of T100M+ PLC for
host-link communication are: 38400 baud, 8 data bit, 1 stop bit, no parity.
The baud rate and the communication format may be changed using the
“SetBAUD” TBASIC command described in the Programmer’s Reference Part
II - TBASIC.
Multiple Communication Protocols
The competent T100M+ family of PLCs supports many different
communication protocols to allow maximum application flexibility. In
addition to its own native set of communication protocols, the T100M+
PLC also understand and speaks the following protocols:
1. *MODBUS ASCII mode compatible communication protocol.
2. *MODBUS RTU mode compatible communication protocol.
(For Rev D board with Firmware revision r32 and above only)
3. *OMRON Host Link Commands for the C20H PLC family.
4. *emWare EMIT 3.0 compatible protocol - This protocol is
licensed from emWare which allows the T100M+ PLC to be linked
to the Internet via emGateway.
*Note: all trade marks belong to their respective owners.
The native host link command protocol will be described in detail in this
chapter as well as in Chapter 4. The MODBUS and OMRON compatible
protocols will be described in Chapter 5 and in Chapter 6 we will describe
the interface of T100M+ family of PLCs to the emGateway for connection
to the Internet.
Native Mode Communication Protocols
When a T100M+ PLC receives a native host-link command from COMM1
or COMM3, it will automatically send a response string corresponding to
the command. This operation is totally transparent to the user and need
not be handled by the user’s program.
All T100M+ PLCs support both point-to-point (one-to-one) and multi-point
(one-to-many) communication protocols. Each protocol has a different
command structure as described below:
3-1
T100MD+ & MX+ PLC
Chapter 3 : Host Communication
3.1 POINT-TO-POINT COMMUNICATION
In a point-to-point communication system, the host computer's
RS232C serial port is connected to the PLC’s COMM1. At any one
time, only one controller may be connected to the host computer.
The host-link commands do not need to specify any controller ID
code and are therefore of simpler format, as shown below:
Command/Response Block Format (Point to Point)
x
x
Header
....
....
Data
....
*
Terminator
Each command block starts with a two-byte ASCII character
header, followed by a number of ASCII data and ends with a
terminator which comprises an '*' character and a carriage return
(ASCII value = 1310). The header denotes the purpose of the
command. For example, RI for Read Input, WO for Write Output,
etc. The data is usually the hexadecimal representation of numeric
data. Each byte of binary data is represented by two ASCII
characters (00 to FF).
To begin a communication session, the host computer must first send
one byte of ASCII character: Ctrl-E (=05Hex) via its serial port to the
controller. This informs the controller that the host computer wishes to
send a (point-to-point) host-link command to it. Thereafter, the host
computer must wait to receive an echo of the Ctrl-E character from
the controller. Reception of the echoed Ctrl-E character indicates that
the controller is ready to respond to the command from the host
computer. At this moment, the host computer must immediately
send the command block to the controller and then wait to receive
the response block from the controller. The entire communication
session is depicted in Figure 2-1.
After the controller has received the command, it will send a response
block back to the host computer and this completes the
communication session. If the controller accepts the command, the
response block will start with the same header as the command,
followed by whatever information that has been requested by the
command and the terminator.
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
H o s t C o m p u ter
T h e M -s e r ies P L C
Send C trl-E
(05H) and wait
for echo
Ready to process
command: return
C trl-E (05H)
Send C o mma nd
string to controller
W a it for respo nse
E xecute comma nd.
Return Respo nse
string to host
Accept Respo nse
C heck fo r errors
Figure 3.1
If an unknown command is received or if the command is illegal
(such as access to an unavailable output or relay channel), the
following error response will be received:
Error Response Format
E
R
*
The host computer program should always check the returned
response for possibilities of errors in the command and take necessary
actions.
3.2 MULTI-POINT COMMUNICATION SYSTEM
In this system, one host computer may be connected to either a
single T100MD+ (via either RS232 or RS485) or multiple T100MDs,
T100MXs controllers or the H-series PLCs on an RS485 network.
3.2.1 RS485 Network Interface Hardware
The built-in RS-485 interface allows the T100M+ controllers to be
networked together using very low cost twisted-pair cables. RS485 allows up to 32 controllers (including the host computer
3-3
T100MD+ & MX+ PLC
Chapter 3 : Host Communication
node) to be networked together. The twisted-pair cable goes
from node to node in a daisy chain fashion and should be
terminated by a 120 ohm resistor as shown below.
+5V
Tw iste d-p a ir R S 485 n etw o r k c a b le
Termina ting
resistor
+
560
_
R S 485
+
_
Host C o mpute r with
RS -485 or
M-series PLC
+
_
+
_
+
560
_
T100MD +
T100MX+
T28H-R e lay
R S 485
R S 485
R S 485
120Ω
0V
Figure 3.2
Note that the two wires are not interchangeable so they must
be wired the same way to each controller. The maximum wire
length should not be more than 1200 metres (4000 feet). RS485 uses balanced or differential drivers and receivers, this
means that the logic state of the transmitted signal depends on
the differential voltage between the two wires and not on the
voltage with respect to a common ground.
As there will be times when no transmitters are active (which
leaves the wires in "floating" state), it is a good practice to
ensure that the RS-485 receivers will indicate to the CPUs that
there is no data to receive. In order to do this, we should hold
the twisted pair in the logic '1' state by applying a differential
bias to the lines using a pair of 560Ω to 1KΩ biasing resistors
connected to a +9V (at least +5V) and 0V supply as shown in
Figure 3-2. Otherwise, random noise on the pair could be
falsely interpreted as data.
The two biasing resistors are necessary to ensure robust data
communication in actual applications. Some RS485 converters
may already have biasing built-in so the biasing resistors may
not be needed. However, if the master is an M-series PLC then
you should use the biasing resistor to fix the logic states to a
known state. Although in lab environment the PLCs may be
able to communicate without the biasing resistors, their use is
strongly recommended for industrial applications.
3.2.2 Protection of RS485 Interface
The simple, direct multi-drop wiring shown in Figure 3-2 will work
well if all the networked PLCs are in close proximity and they all
share a common power supply. They will even work for long
distance as long as no wiring error ever occurred. However, in
an industrial environment, the PLCs are most likely far apart and
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
they each may have their own power supply. Since processes
are often modified regularly and if one day somebody by
mistake shorts one of the PLC’s RS485 to high voltage, all the
PLCs connected to the same RS485 wiring will be fried
simultaneously. This can result in very costly down time for the
whole process, since all the PLCs connected to the network will
need to be repaired.
Hence, for networking over long distances and involving more
than a few PLCs, it is important to protect the RS485 interface.
We strongly recommend the following protection circuit to be
added between every PLC’s RS485 and the twisted pair multidrop network cable for such applications:
RS485 Network
+
10 W 1/2 W 0.1A Fuses
RS485
24V
9V 1W
Zener
Power
0V
Ground the
Shield
Figure 3.3
Note:
• As can be seen from the circuit, the two 9V Zener diodes
clamp the signal voltage to the PLC’s RS485 interface to
between +9V and - 0.7V. If the high voltage persists, the 0.1A
fuse will blow, effectively disconnecting the PLC from the
offending network voltage.
• You should use shielded twisted pair cables as the multi-drop
network “backbone” and connect the shield to the 0V (DC
ground) power terminal of every PLC. The grounded shield
then provides a common ground reference for all the different
PLCs’ power supplies. Even though the RS485 network may still
work without a common ground reference because the signal
wire pair will somehow “pull” all the RS485 to some reference
point. Failure to provide a common ground is a potential
source of serious trouble
trouble as signal wires with a floating ground
easily induce large voltage differences between nodes when
subjected to electromagnetic interference. Hence for reliable
operation it is important to provide the common ground. A
3-5
T100MD+ & MX+ PLC
Chapter 3 : Host Communication
grounded shield also has the additional advantage of
shielding the electrical signals from EMI.
3.2.3 Single Master RS485 Networking Fundamentals
RS485 is a half-duplex network, i.e., the same two wires are
used for both transmission of the command and reception of
the response. Of course, at any one time, only one transmitter
may be active. The T100M+ controllers implement
master/slave network protocols. The network requires a master
controller, which is typically a microcomputer equipped with an
RS485 interface. In the case of an IBMPC or AT, you can
purchase an RS-485 adapter card or an RS232C-to-RS485
converter and connect it to the RS232C serial port. A T100M+
PLC can also be programmed to act as the master, it can
communicate with other PLCs by executing the “NETCMD$”
function or the “READMODBUS” or the “WRITEMODBUS”
commands (the latter two are for communicating using
MODBUS protocols only).
Only the master can issue commands to the slave controllers.
To transmit a command, the master controller must first enable
its RS-485 transmitter and then send a multi-point command to
the network of controllers. After the last stop bit has been sent,
the master controller must relinquish the RS485 bus by disabling
its RS485 transmitter and enabling its receiver. At this point the
master will wait for a response from the slave controller that is
being addressed. Since the command contains the ID of the
target controller, only the controller with the correct ID would
respond to the command by sending back a response string.
For the network to function properly, it is obvious that no two
nodes can have the same ID. You can use the “Controller ->
Target Access -> Write ID Address” command in TRiLOGI to set
the ID for each M-series PLC. You can also use the "IW”
command to set the device ID. Also, all nodes must be
configured to the same baud rate and communication format.
Also, care should be taken to ensure that the power supplies for
all the controllers are properly isolated from the main so that no
large ground potential differences exist between any controllers
on the network.
3.2.4
MultiMulti-Masters RS485 Networking Fundamentals
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
Since any T100MD or T100MX is capable of sending out network
commands, the obvious question is whether multiple masters
are allowed on the RS485 network? It is possible to have
multiple masters on a single RS485 network provided the issues
of collision and arbitration are taken care of. There are several
means to achieve these objectives:
1) Multiple Access with Collision Detection
There is nothing to stop any PLC from sending out host-link
commands to other PLCs. However, If more than one PLC
simultaneously enables their transmitters and send out hostlink commands, then the signals will conflict and the
messages will be garbled up. If the network traffic is low,
then the solution may be a matter of having the master
check for the correct response after sending out a
command string. If there is error in the response string, the
master should back off the network for a short while (use
different timing for different PLCs) and then re-send the
command until a correct response string is obtained. This
scheme is similar to the CSMA/CD (Carrier Sensing Multiple
Access/Collision-Detection) commonly used in Ethernet.
Fortunately, the “NETCMD$” function of T100M+ PLC
automatically senses the RS485 lines until they are free
before sending out the command string to reduce the
chance of a collision. It also checks the integrity of the
response string for correct FCS (Frame Check Sequence)
characters before returning the string (Please refer to the
Programmer’s Reference for detail description of the
NETCMD$( ) function).
However, the program must still check the following items in
the response string to verify that the string returned from
NETCMD$( ) function indeed comes from the PLC that it had
talked to and not from another PLC (which tries to send a
command to someone else):
i) The ID is correct
ii) The header is identical to the command string
iii) The length of response string is correct.
Pros and Cons: This method does not incur any hardware
cost, but it requires careful programming and strict checking
of the response string and hence requires more effort to
program. It is also the least desirable if the network traffic is
moderately high as many collisions will occur and there is
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
danger of some undetected error being allowed to pass
through.
2) Token Awarding Scheme
A “token” is a software means of telling a PLC that it has
been given the right to temporarily act as the master. A
T100MD+ PLC or a host PC can serve as the token master.
An internal relay bit or a variable of the PLC can be defined
as the token. The token master will begin by giving the token
(i.e., by setting the token relay bit to ‘1’ or the token variable
to some fixed value) to the first PLC on the list. The PLC that
has the token can then send host-link commands to other
PLCs. When it has finished the job it can then send a
command to the token master to relinquish its token. If it is
based on a fixed timing scheme the master can assume
that the PLC will complete its job after a fixed time (say 0.1
seconds) and turn off its corresponding token relay bit.
The token master then passes the token to the next PLC on
the list and so on until the last PLC has relinquished its token,
and the token is passed back to the first PLC on the list
again. This way at any one time there will only be one active
network master (the one with the token) and hence there is
no danger of conflicting signals or garbled messages to
handle.
Pros and Cons: This method also does not incur any
hardware cost, but it requires the programmer to draw up a
plan on what internal relay or variable to use as the token
and how the PLC can relinquish its token to the token master.
(It could be by fixed timing or by returning a message to
relinquish the token) It is a challenging job for programmers
unfamiliar with networking scheme, but with some
experimentation it can be achieved readily.
3) Rotating Master Signal
In this scheme we make use of the digital inputs of the
T100M+ PLCs to grant the PLC the right to act as the network
master. Lets call this input the “Be the Master” input. We can
use a low cost H-series PLC running a sequencer to activate
the “Be the Master” input line of each PLC one at a time.
Each PLC is given a fixed amount of time to be the master
(e.g. 0.1s each). Only when the “Be the Master” input is ON
can the T100M+ PLC start sending out host-link commands
to other PLCs. So at any one time there will only be one
master on the network and no conflict will occur as a result.
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
Pros and Cons: This method is the easiest to program since
there is no need to handle the token with the token master
or perform extensive error check on the response string.
However, this method uses one input of each PLC and as
many outputs on the master-signal generator PLC as there
are PLC masters. It also requires wiring the PLCs to the
master-signal generator PLC and hence is the most costly
method of all.
3.2.5 Command/Response Block Format (Multi(Multi-point)
@
n
n
x
x
.... .... ....
Device ID Header
x
Data
x
*
FCS Terminator
Each command block starts with the character "@" and twobyte hexadecimal representation of the controller's ID (00 to FF),
and ends with a two-byte "Frame Check Sequence" (FCS) and
the terminator. FCS is provided for detecting communication
errors in the serial bit-stream. If desired, the command block
may omit calculating the FCS simply by putting the characters
"00" in place of the FCS.
Calculation of FCS
The FCS is 8-bit data represented by two ASCII characters (00 to
FF). It is a result of Exclusive OR sequentially performed on each
character in the block, starting from @ in the device number to
the last character in the data. An example is as follow:
@
0
4
Device ID
@
0
4
R
V
I
R
V
I
A
Header Data
4
8
*
FCS
0100 0000
XOR
0011 0000
XOR
0011 0100
XOR
0101 0010
XOR
0101 0110
XOR
0100 1001
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T100MD+ & MX+ PLC
A
Chapter 3 : Host Communication
XOR
0100 0001
0100 1000 = 4816
Value 4816 is then converted to ASCII characters '4' (0011 0100)
and '8' (0011 1000) and placed in the FCS field.
FCS calculation program example
The following C function will compute and return the FCS for the
"string" passed to it.
unsigned char compute_FCS(unsigned char *string){
unsigned char result;
result = *string++;
/*first byte of string*/
while (*string)
result ^= *string++; /* XOR operation */
return (result);
}
3.2.6
Communication Procedure
Unlike the point-to-point communication protocol, the host
computer must NOT send the CTRL-E character before sending
the command block. After the host computer has sent out the
multi-point host-link command block, only the controller with the
correct device ID will respond. Hence it is essential to ensure
that every controller on the RS485 network assumes a different
ID. Otherwise, contention may occur (i.e., two controllers
simultaneously sending data on the receiver bus, resulting in
garbage data being received by the host). On the other hand,
if none of the controller IDs match that specified in the
command block, then the host computer will receive no
response at all.
The PLC automatically recognizes the type of command
protocols
(point-to-point or multi-point) sent by the host
computer and it will respond accordingly. If a multi-point
command is accepted by the controller, the response block
will start with a character '@', followed by its device ID and the
same header as the command. This will be followed by the
data requested by the command, a response block FCS and
the terminator.
Framing Errors
When the controller receives a multi-point host-link command
block, it computes the FCS of the command and compares it
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
with the FCS field received in the command block. If the two do
not match, then a "framing error" has occurred. The controller
will send the following Framing Error Response to the host:
Framing Error Response Block (Multi-point only)
@
x
x
F
E
x
Device ID Header
x
FCS
*
Terminator
Command Errors
If an unknown command is received or if the command is illegal
(such as an attempt to access an unavailable channel), the
following error response will be received:
Error Response Format
@
x
x
E
Device ID
R
x
Header
x
FCS
*
Terminator
The host computer program should always check the returned
response for possibilities of errors in the command and take
necessary action.
3.3 USING NETWORK TRiLOGI
If you have connected the RS485 interface of a few T100M+ PLCs
into a multi-drop network, you may download the program or monitor
the operation of any PLC from a single host computer connected to
the network. Note that the host computer’s RS485 adapter must be of
approved type to be compatible with the NETWORK-TRiLOGI.
* The Internet TRiLOGI Version 5.0 is designed to support both single
and multiple M-series PLCs linked to a single PC running the
TLServer, hence there is no need to run a separate program.
However, the DOS version of TRiLOGI Version 4.1x uses two different
setups of the TL41.EXE program to handle connection to single or
multiple PLCs connection. The following descriptions is only
applicable to the DOS version of TRiLOGI Version 4.1x.
The network version of TRiLOGI Version 4.1x is available by executing
the batch file “TL4NET.BAT” in the “trilogi\tl4” directory. The network
version of the program is almost identical to TL4.EXE, the exception
being an additional command item "Select Controller Ctrl-I" in the
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
"Controller" main menu. For this program to function properly, each
PLC on the network must be assigned a unique ID. You can use the
command in TRiLOGI: “Controller ->Target Access -> Write ID
Address” to set the ID of each controller separately before connecting
them to the network. When running the "TL4NET” program you can
easily select any specific PLC to work with by specifying its ID.
After entering the device ID, Network TRiLOGI will automatically query
the PLC with that particular ID for its source file name. It then searches
the current directory of the PC's disk drive for a matching file. If found,
it will prompt the user to confirm whether he/she wishes to open the
source file. The selected controller is then available for programdownloading or On-line/Ladder monitoring as per the normal TRiLOGI
operation. To switch to another PLC, simply press <Ctrl-I> and enter
another ID. This program offers a quick way to test a new RS485
network.
If a communication error occurs, check to see if the PLC's ID has
been properly defined. Next check for loose or incorrect wiring to the
RS485 terminal. Also check to ensure that the host-link port selection
DIP switch SW1-2 on the PLC has been turned ON. The 8-pin DIP IC -SN75176 provides the RS485 interface and it may be necessary to
replace it if it is damaged during installation as a result of over
voltage/current or prolonged short-circuit of its two terminals, etc.
Note that at any one time only one PC or controller may act as the
master in the network. Hence when running TL4NET program, the PC is
the sole master and all the T100M+ PLCs must be slaves only. If any
T100M+ attempts to send commands when TL4NET is performing online monitoring, conflict will occur and the TL4NET program may
experience frequent “No Communication” errors.
3.4 TROUBLE-SHOOTING An RS485 NETWORK
a) Single faulty device
If a single device on the RS485 network becomes inaccessible,
problems can be isolated to this particular device. Check for
loose or broken wiring or wrong DIP switch settings. Also double
check the device ID using the host-link command "IR*" sent via
the RS232C port of the PLC. If all attempts fail, either replace the
entire PLC or the SN75176 chip that handles the RS485 interfacing
and try again.
b) Multiple faulty devices
If all the PLCs are inaccessible by the host computer, it may
possibly be due to a faulty RS232C-to-RS485 converter at the PC.
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T100MD+ & MX+ PLC
Chapter 3 : Host Communication
If this is the case, disconnect the RS485 converter from the
network and check it using a single PLC. Also check to ensure that
the converter has been properly configured with the correct DIP
switch settings. Replace the converter if it is confirmed to be
faulty. Next check the wire from the converter to the beginning of
the network. A broken wire here can lead to the failure of the
entire network.
Since an RS485 network links many PLCs together electrically and
in a daisy chain fashion, problems occurring along the RS485
network sometimes affect the operation of the entire network. For
example, a broken wire at the terminal of one node may mean
that all the PLCs connected after this node become inaccessible
by the master. If the RS485 interface of one of the PLCs has shortcircuited because of component failure, then the entire network
goes down with it too. This is because no other node is able to
assert proper signals on the two wires that are also common to
the shorted device.
Hence when trouble-shooting a faulty RS485 network, it may be
necessary to isolate all the PLCs from the network. Thereafter,
reconnect one PLC at a time to the network, starting from the
node nearest to the host computer. Use network TRiLOGI to check
communication with each PLC until the faulty unit has been
tracked down.
3-13
Chapter 4 Command/Response Format
This section describes the detail formats of the command and response
blocks for all M-series PLC host link commands. Only the formats for the
point-to-point communication system are presented, but all these
commands are available to the multi-point system as well. To use a
command for multi-point system, simply add the device ID (@nn) before
the command header and the FCS at the end of the data (See Chapter 3
for detailed descriptions of multi-point communication command format).
4.1 Device ID Read
Command Format
*
I
R
Response Format
I
R
161
160
*
Device ID (00 to FF)
The device ID is to be used for multi-point communication protocol
where the host computer can selectively communicate with any
controller connected to a common RS485 bus (see Section 3 for
details). The ID has no effect for point-to-point communication.
The device ID is stored in the PLC's EEPROM and therefore will remain
with the controller until it is next changed.
4.2. Device ID Write
Command Format
I
W
161 160
*
Device ID (00 to FF)
Response Format
*
I
W
E.g. To set the PLC’s ID to 0A, send command string “IW0A*” to PLC.
4.3 Read Input Channels
Command Format
R
I
n
n
*
8-bit Channel # (Hex)
Response Format
4-1
T100MD+ & MX+ PLC
R
I
Chapter 4: Command/Response Format
161
160
*
8-bit Data (Hex)
Definition of Input Channels
The following table shows the input numbers as defined in TRiLOGI's
Input entry table corresponding to the input channel number.
CH00:
CH01:
CH02:
CH03:
CH04:
CH05:
CH06:
CH07:
CH08:
CH09:
CH0A16:
CH0B16:
CH0C16:
CH0D16:
CH0E16:
CH0F16:
Bit7
8
16
24
32
40
48
56
64
72
80
88
96
104
112
120
128
7
15
23
31
39
57
55
63
71
79
87
95
103
111
119
127
Input/Output Numbers
6
5
4
14
13
12
22
21
20
30
29
28
38
37
36
56
45
44
54
53
52
62
61
60
70
69
68
78
77
76
86
85
84
94
93
92
102
101
100
110
109
108
118
117
116
126
125
124
3
11
19
27
35
43
51
59
67
75
83
91
99
107
115
123
2
10
18
26
34
42
50
58
66
74
82
90
98
106
114
122
Bit0
1
9
17
25
33
41
49
57
65
73
81
89
97
105
113
121
The 8-bit inputs of each channel is represented by two bytes ASCII text
expression of its hexadecimal value. For example: if inputs 1 to 3 are
logic '0's, inputs 4 to 10 are logic '1's and all other inputs are logic '0's,
then if you send command “RI00*”, you will get response “RIF8*” (F816
=1111 10002).
4.4 Read Output Channels
Command Format
R
O
n
n
*
8-bit Channel # (Hex)
Response Format
R
O
161
160
*
8-bit data (Hex)
Please refer to the Input/Output vs Channel Number table described
in the last section “3. Read Input Channels” for details.
4-2
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.5 Read Relay Channels
Command Format
R
R
n
n
*
8-bit Channel # (Hex)
Response Format
R
161
R
160
*
8-bit data (Hex)
Definition of Relay Channel Numbers
All M-series PLC supports 256 internal relays, the channel definition of
the first 128 internal relays is the same as the inputs and the outputs.
The remaining relays and their assigned channels are shown in the
following table:
bit7
Relay numbers
bit0
CH1016:
CH1116:
CH1216:
CH1316:
CH1416:
CH1516:
CH1616:
CH1716:
CH1816:
CH1916:
CH1A16:
CH1B16:
CH1C16:
CH1D16:
CH1E16:
CH1F16:
136
144
152
160
168
176
184
192
200
208
216
224
232
240
248
256
135
143
151
159
167
175
183
191
199
207
215
223
231
239
247
255
134
142
150
158
166
174
182
190
198
206
214
222
230
238
246
254
133
141
149
157
165
173
181
189
197
205
213
221
229
237
245
253
132
140
148
156
164
172
180
188
196
204
212
220
228
236
244
252
131
139
147
155
163
171
179
187
195
203
211
219
227
235
243
251
130
138
146
154
162
170
178
186
194
202
210
218
226
234
242
250
129
137
145
153
161
169
177
185
193
201
209
217
225
233
241
249
4.6 Read Timer Contacts
Command Format
R
T
n
n
*
8-bit Channel # (Hex)
Response Format
R
T
161
160
*
8-bit data in Hex
Definition of TimerTimer-Contact Channel Numbers
4-3
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
A timer contact is a single bit of memory and 8 timer contacts are
grouped into one 8-bit channel similar to that of the inputs, outputs etc.
The following table shows the timer numbers defined in TRiLOGI's
Timer entry table and their corresponding channel numbers.
CH0:
CH1:
CH2:
CH3:
CH4:
CH5:
CH6:
CH7:
8
16
24
32
40
48
56
64
7
15
23
31
39
57
55
63
6
14
22
30
38
56
54
62
5
13
21
29
37
45
53
61
4
12
20
28
36
44
52
60
3
11
19
27
35
43
51
59
2
10
18
26
34
42
50
58
1
9
17
25
33
41
49
57
4.7 Read Counter Contacts
Command Format
R
C
n
n
*
8-bit Channel # (Hex)
Response Format
R
C
161 160
*
8-bit data in Hex
Definition of CounterCounter-Contact Channel Numbers:
The 64 counter contacts are assigned channel # in exactly the same
way as the 64 timers. Please refer to last section :“6. Read Timer
Contacts” for details.
4.8 Read Timer Present Value (P.V.)
Command Format
R
M
n
n
*
nn: Timer1=00, ..... Timer16=0F.... Timer64=3F
Response Format
R
M 103 102
101 100
*
Timer present value in Decimal
The present value (PV) of the specified timer is returned in decimal
form as four byte ASCII text characters from 0000 to 9999.
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T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.9 Read Timer Set Value (S.V.)
Command Format
R
m
n
n
*
nn: Timer1=00, ..... Timer16=0F.... Timer64=3F
Response Format
R
m 103 102
101
100
*
Timer Set Value in Decimal
The Set Value (S.V.) of the specified timer is returned in decimal form
as four byte ASCII text characters from 0000 to 9999. Note that this
command header contains small letter “m” instead of “M” in the “RM”
command.
4.10 Read Counter Present Value (P.V.)
Command Format
R
U
n
n
*
nn: Counter1=00, ..... Counter16=0F.... Counter64=3F
Response Format
R
U 103 102
101
100
*
Counter present value in Decimal
The Present Value of the specified counter is returned in decimal form
as four byte ASCII text characters from 0000 to 9999.
4.11 Read Counter Set Value (S.V.)
Command Format
R
u
n
n
*
nn: Counter1=00, ..... Counter16=0F.... Counter64=3F
Response Format
R
u
103 102
101
100
*
Counter Set Value in Decimal
The Set Value of the specified counter is returned in decimal form as
four byte ASCII text characters from 0000 to 9999. Note that this
header contains small letter “u” instead of “U” in the “RU” command.
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T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.12 Read Variable - Integers (A to Z)
Command Format
R
V
alphabet
I
*
A,B.C....Z
Response Format
I
R
V
167
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
E.g. To read the value of the variable “K”, send host-link command
“RVIK*”. If variable K contains the value 12345610 (=1E24016),
PLC will send the response string as “RVI0001E240*”.
4.13 Read Variable - Strings (A$ to Z$)
Command Format
alphabet
R
V
$
*
A,B.C....Z
Response Format
a
R
V
$
a
a
...
...
a
a
a
*
ASCII characters of the string (variable length)
E.g. To read the value of the string variable “M$”, send host-link
command “RV$M*”. If variable M$ contains the string “Hello
World”, the PLC will send the response string as “RV$Hello
World*”.
4.14 Read Variable - Data Memory (DM[1] to DM[4000])
Command Format
R
V
D
163
162
161
160
*
0001 to 0FA0 (400010)
Response Format
R
V
D 163
162
161
160
*
4 Hexadecimal Digit for 16-bit integer
E.g. To read the value of DM[3600], send host-link command
“RVD0E10*”. If variable DM[3600] contains the value 1234510
(=303916), PLC will send the response string as “RVD3039*”.
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T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.15 Read Variable - System Variables
This command allows you to read all the M-series PLC’s 16-bit system
variables such as the inputs[ ], outputs[ ], relays[ ], counters[ ], timers[
], timers’ P.V., counters’ P.V., CLK[ ] and DATE[ ]. Although inputs,
outputs etc. are also accessible via the “RI”, “RO”, “RR”...
commands, the RVS command can access them as 16-bit words
instead of as 8-bit bytes in those commands. For the 32-bit system
variable HSCPV[ ], use the “RVH” command described in the next
section to access it. It may be more conventional for some SCADA
software driver to use a single header command “RVS” to access all
the I/O, varying only the “type” number to access different I/O types.
The RVS command also can be used to access the internal
variables used to store ADC, DAC and PWM values obtained during
the latest execution of the ADC(), setDAC or setPWM statement.
These are however not system variables in TBASIC sense. E.g. it is
illegal to use ADC[2] to access the ADC channel #2 in TBASIC (you
have to use the ADC(2) function instead). An 8-bit hexadecimal
number is used to denote the “type” of system variable, as shown in
the following table:
System
type
System
type
Variable
Variable
input[ ]
01
clk[ ]
08
output[ ]
02
date[ ]
09
relay[ ]
03
0A
timer[ ]
04
ADC*
0B
ctr[ ]
05
DAC*
0C
timerPV[ ]
06
PWM*
0D
* Not a system variable
ctrPV[ ]
07
in TBASIC
Command Format
R
V
S
n
n
type
161
160
*
Index
type (01 to 0D) - denote the type of system variable to access,
index (01 to 1F) - index into the array, starting from 01.
Response Format
R
V
S
163
162
161
160
*
4 Hexadecimal Digit for 16-bit integer
4-7
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
Example: To read the value of DATE[2] (which represents the month
of the RTC), send command “RVS0902*” and if the PLC
responds with “RVS0005” it means the month is May.
4.16 Read Variable - High Speed Counter HSCPV[ ]
Command Format
R
V
H
n
*
Channel: 1 or 2
Response Format
R
V
H
167
166
165
164
163
162
161
160
*
8 Hexadecimal Digit for 32-bit integer
E.g. To read the value of HSCPV[2], send hostlink command
“RVH2*”. If variable HSCPV[2] contains the value 12345610
(=1E24016), PLC will send the response string as
“RVH0001E240*”.
4.17 Write Inputs
Command Format
W
I
n
n
Channel #
(00 to 0F)
161
160
*
Data
Response Format
*
W
I
4.18 Write Outputs
Command Format
W
O
n
n
Channel #
(00 to 0F)
161
160
*
Data
Response Format
*
W
O
4-8
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.19 Write Relays
Command Format
W
R
n
161
n
Channel #
Response Format
*
W
R
160
*
Data
4.20 Write Timer-contacts
Command Format
W
T
n
161
n
Channel #
(00 to 07)
160
*
Data
Response Format
*
W
T
4.21 Write Counter-contacts
Command Format
W
C
n
n
161
Channel #
(00 to 07)
160
*
Data
Response Format
*
W
C
4.22 Write Timer Present Value (P.V.)
Command Format
W
M
n
n
103
102
101
100
*
Timer1=00,
New timer PV
........
Timer64=3F (Hex)
4-9
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
Response Format
*
W
M
Please note that the timer number starts from 00 which represent
timer #1, 01 represents timer #2... and so on.
4.23 Write Timer Set Value (S.V.)
Command Format
W
m
n
n
103
102
101
100
*
Timer1=00,
New timer SV
....
Timer64=3F (Hex)
Response Format
*
W
m
Note: the 2nd character is a lower case “m” instead of the upper case
“M” of “WM” command.
4.24 Write Counter Present Value (P.V.)
Command Format
W
U
n
n
103
102
101
100
*
100
*
Counter1=00,
New PV
....
Counter64=3F (Hex)
Response Format
*
W
U
4.25 Write Counter Set Value (S.V.)
Command Format
W
u
n
n
103
102
101
Counter1=00, New Counter SV
....
Counter64=3F (Hex)
4-10
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
Response Format
*
W
u
Note: the 2nd character is a lower case “u” instead of the upper case
“U” of the “WU” command.
4.26 Write Variable - Integers (A to Z)
Command Format
I alphabet
W V
167 166 165 164 163 162 161 160
A,B.C....Z
*
8 Hexadecimal Digit for 32-bit integer
Response Format
*
I
W
V
E.g. To assign variable “K” to number 5678910(=0DD516), send
hostlink command “WVIK00000DD5*”.
4.27 Write Variable - Strings (A$ to Z$)
Command Format
W
V
$ alphabet
a
A,B.C....Z
a
...
...
a
a
*
ASCII characters of the
string (variable length)
Response Format
*
W
V
$
E.g. To assign the string “T100MD+ Super PLC” to the string
variable P$, send hostlink command “WV$PT100MD+ Super
PLC*”.
4.28 Write Variable - Data Memory (DM[1] to DM[4000])
Command Format
W
V
D
163
162
161
160
16-bit Index to array
0001 to 0FA0 (400010)
163
162
161
160
*
16-bit Integer Data
4-11
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
Response Format
W
V
D
*
E.g. To write the value 123410 (=4D216)to DM[1000], send hostlink
command “WVD03E804D2*”. (100010 = 3E816)
4.29 Write Variable - System Variables
System
Variable
input[ ]
output[ ]
relay[ ]
timer[ ]
ctr[ ]
timerPV[ ]
ctrPV[ ]
type
System
Variable
clk[ ]
date[ ]
ADC*
DAC*
PWM*
01
02
03
04
05
06
07
type
08
09
0A
0B
0C
0D
* Not a system variable in TBASIC
Command Format
W
V
S
n
type
n
161
160
163
Index
162
161
160
*
16-bit Integer Data
type (01 to 0D) - denote the type of system variable to access,
index (01 to 1F) - index into the array, starting from 01.
Response Format
W
V
S
*
Example: To set clk[1] (which represents the hour of the RTC) to 14,
send the command “WVS0801000E*” to the PLC.
4.30 Write Variable - High Speed Counter HSCPV[ ]
Command Format
W V H n 167 166 165 164 163 162 161 160
1 or 2
*
8 Hexadecimal Digit for 32-bit integer
Response Format
*
W
V
H
E.g. To clear the value of HSCPV[2],
“WVH200000000*”.
send hostlink command
4-12
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.31 Update Real Time Clock Module
Command Format
*
W
r
Response Format
*
W
r
If the battery-backed MX-RTC module is installed, this command
forces he PLC to write the values of the TIME[ ] and DATE[ ]
variables into the RTC module. This command will be ignored by
a PLC without the RTC module.
4.32 Halting the PLC
Command Format
*
C
2
Response Format
*
C
2
When the PLC receives this command, it temporarily halts the
execution of the PLC's ladder program after the current scan.
However, the PLC continues to scan the I/Os and processes host link
commands sent to it and will report the current I/O data and internal
variables to the host computer.
4.33 Resume PLC Operation
Command Format
*
C
1
Response Format
*
C
1
When the PLC receives this command, it will resume execution of
the ladder program if it has been halted previously by the "C2"
command. Otherwise, this command has no effect.
4-13
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.34 Host Communication Program Examples
You can try out all the hostlink commands described in this chapter
using TRiLOGI 4.1x built-in “Host Link Command” feature under the
“Controller” menu. (For Internet TRiLOGI Version 5.x this function is not
supported on TRiLOGI Client but is supported on the TLServer under
the serial communication setup.) Try entering a point-to-point or a
multi-point command string and observe the response string. If you
have changed some data using the write command, then activate
On-Line Monitoring and examine the changes made using the “View
Variables” window.
Two sample programs, one written in Microsoft QBASIC
(HOST485.bas) and the other written in Borland International's Turbo C
(HOST485.C), are provided in the TRiLOGI distribution diskette to help
programmers get started. Both programs essentially perform the
same functions, as follows:
(a) Prompt the user to enter the desired command block via the
PC's keyboard.
(b) Initiate a communication session and send the command
string to the controller.
(c) Wait to receive the response block from PLC and display the
response block on the PC's screen.
These two programs incorporate all the codes needed to
communicate successfully with the M-series PLC in either BASIC or C
language using the point-to-point or multi-point protocols. The
programs will work on both the COMM1 (RS232) port as well as
COMM3 (RS485) port. Programmers can therefore build their
applications using either of the programs as building blocks.
These two programs assume that an RS232-to-RS485 adapter is
used such that the direction of communication of the RS485 bus is
controlled by the state of /RTS line of the RS232C. The programs
accept both point-to-point and multi-point commands from the
keyboard and automatically initiate the correct communication
protocols with the controller. If your RS485 adapter works differently
then you must modify the functions "transmit485()" and
"receive485()" to control the direction of the half-duplex RS485
bus. Please refer to the technical manual of your RS485 adapter for
details.
The PLC must be assigned an ID using the “IW” hostlink command
which you can send using TRiLOGI’s “Host Link Command” item
under the “Controller” menu. (Or at TLServer for Internet TRiLOGI)
4-14
T100MD+ & MX+ PLC
Chapter 4: Command/Response Format
4.35 Inter-Networking Using NETCMD$ Command
All M-series PLCs are able to send out host link commands to other
M-series or H-series PLCs using the built-in TBASIC function
NETCMD$(). This function accepts host link commands in multipoint format and automatically computes the Frame Check
Sequence (FCS) characters, append them to the command string
and send out the whole command string together with the
terminators. The function then waits for a response string and
checks the integrity of the received response string for error. This
function returns a string only if a proper response string has been
received. Please refer to the TBASIC Reference manual for detailed
explanation of this command.
The NETCMD$() function therefore greatly simplifies the
programming tasks for handling networking between PLCs. The
programmer only needs to construct the correct command string
according to the formats described in this chapter, pass the
formatted string to the NETCMD$() function and then check for the
response string. An M-series PLC may use the NETCMD$ to map the
I/O of another PLC into its internal relays and use the other PLC as its
remote I/O.
There are two programming examples in your “TRILOGI\TL4”
directory which illustrate the use of NETCMD$() to map I/O of slave
PLC to the master. Please study the two examples: “REMOTEH.PC4” and “REMOTE-M.PC4”
carefully to understand the
mechanism of mapping I/Os between the PLC. The TRiLOGI
program “REMOTE-H.PC4” will work on both H- and M-series PLCs
as slaves , whereas the program “REMOTE-M.PC4” will only work
with M-series slave PLC. This is because the M-series host link
command set is a superset of H-series host link command set, and
this example uses the more efficient M-series host link commands
to read/write 16-bit data for networking between M-series PLC.
4.36 Inter-Networking Using MODBUS Protocols
The T100M+ PLCs may also pass data to each other using special
MODBUS commands which are even simpler to use than NETCMD$
but are restricted to accessing variables that are mapped into
MODBUS address structure. Please refer to the next chapter as well
as the TBASIC Reference manual for details on using the
READMODUS and WRITEMODBUS commands.
4-15
Chapter 5 MODBUS /OMRON Protocols Support
The T100M+ PLC supports a subset of the OMRON and MODBUS (Both
ASCII and RTU modes are now supported) compatible communication
protocols so that it can be easily linked to third-party control
software/hardware products such as SCADA software, touch panels etc. The
PLC automatically recognizes the type of command format and will
respond with the correct response. These are accomplished without any
user intervention and without any need to configure the PLC at all!
Both MODBUS and Omron protocols use the same device ID address (00 to
FF) as the native protocol described in Chapter 3. Since the addresses of
I/O and internal variables in the T100M+ PLC are organized very differently
from the OMRON or Modicon PLCs, we need to map these addresses to
the corresponding memory areas in the other PLCs so that they can be
easily accessed by their corresponding protocols. All I/Os, timers, counters,
internal relays and data memory DM[1] to DM[4000] are mapped as shown
in table 5.1. However, 32 bit variables and string variables are not mapped
since they are fundamentally quite different in their implementation among
different PLCs. Internal variables which are not mapped can be still be
accessed by copying the contents of these variables to unused data
memory DM[n] (these can be easily accomplished within a CusFn ) so that
they can be accessed by these third party protocols.
For normal application Table 5.1 may be all that you need to interface to
third party control products such as a touch screen LCD panel.
5.1 MODBUS ASCII Protocol Support
T100M+ supports MODBUS ASCII protocols with the following command
and response format:
START
:
Address
2 chars
Function
2 chars
Data
# chars
LRC Check
2 chars
CRLF
2 chars
The following Function Codes are supported:
02
03
05
06
16
Read Input Status
Read Holding Registers
Force Single Coil. Coil #1 = 40001.1, Coil #2 =
40001.2 …. Coil # 17 = 40002.1 and so on.
Preset Single Register
Preset Multiple Registers
Please refer to the MODBUS protocol published by Groupe Schneider at
http://www.modicon.com to find out the exact address and data format
of the MODBUS command and response.
5-1
T100MD+ & MX+ PLC
Chapter 5 : Modbus/Omron Protocols Support
Table 5.1: Memory Mapping of T100M+ to other PLCs
T100M+ I/O #
OMRON
MODBUS Word
Addr. mapping
Input
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
Output
n
1 to 16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
Timer
n
1 to 16
17 to 32
33 to 48
49 to 64
Counter
n
1 to 16
17 to 32
33 to 48
49 to 64
Relay
MODBUS Bit
Addr. Mapping
IR00.0 to IR00.15
IR01.0 to IR01.15
IR02.0 to IR02.15
IR03.0 to IR03.15
IR04.0 to IR04.15
IR05.0 to IR05.15
40001.1 to 40001.16
40002.1 to 40002.16
40003.1 to 40003.16
40004.1 to 40004.16
40005.1 to 40005.16
40006.1 to 40006.16
IR16.0 to IR16.15
IR17.0 to IR17.15
IR18.0 to IR18.15
IR19.0 to IR19.15
IR20.0 to IR20.15
IR21.0 to IR21.15
40017.1 to 40017.16
40018.1 to 40018.16
40019.1 to 40019.16
40020.1 to 40020.16
40021.1 to 40021.16
40022.1 to 40022.16
IR32.0
IR33.0
IR34.0
IR35.0
to
to
to
to
IR32.15
IR33.15
IR34.15
IR35.15
40033.1 to 40033.16
40034.1 to 40034.16
40035.1 to 40035.16
40036.1 to 40036.16
IR48.0
IR49.0
IR50.0
IR51.0
to
to
to
to
IR48.15
IR49.15
IR50.15
IR51.15
40049.1 to 40049.16
40050.1 to 40050.16
40051.1 to 40051.16
40052.1 to 40052.16
n
1 to16
17 to 32
33 to 48
49 to 64
65 to 80
81 to 96
256 + n
257 to 272
273 to 288
289 to 304
305 to 320
321 to 336
337 to 352
512+n
513 to 528
529 to 544
545 to 560
561 to 576
768 + n
769 to 784
785 to 800
801 to 816
817 to 832
n
1 to 16
17 to 32
33 to 48
49 to 64
IR64.0
IR65.0
IR66.0
IR67.0
to
to
to
to
IR64.15
IR65.15
IR66.15
IR67.15
40065.1 to 40065.16
40066.1 to 40066.16
40067.1 to 40067.16
40068.1 to 40068.16
1024 + n
1025 to 1040
1041 to 1056
1057 to 1072
1073 to 1088
65 to 80
81 to 96
97 to 112
113 to 128
IR68.0
IR69.0
IR70.0
IR71.0
to
to
to
to
IR68.15
IR69.15
IR70.15
IR71.15
40069.1 to 40069.16
40070.1 to 40070.16
40071.1 to 40071.16
40072.1 to 40072.16
1089 to 1104
1105 to 1120
1121 to 1136
1137 to 1152
129 to 144
145 to 160
161 to 176
177 to 192
IR72.0
IR73.0
IR74.0
IR75.0
to
to
to
to
IR72.15
IR73.15
IR74.15
IR75.15
40073.1 to 40073.16
40074.1 to 40074.16
40075.1 to 40075.16
40076.1 to 40076.16
1153 to 1168
1169 to 1184
1185 to 1200
1201 to 1216
193 to 208
209 to 224
..
497 to 512
IR76.0 to IR76.15
IR77.0 to IR77.15
..
IR96.0 to IR96.15
40077.1 to 40077.16
40078.1 to 40078.16
..
40097.1 to 40097.16
1217 to 1232
1233 to 1248
..
1521 to 1536
* MODBUS is a registered trademark of Groupe Schneider.
OMRON is a registered trademark of OMRON Corporation.
5-2
T100MD+ & MX+ PLC
Chapter 5 : Modbus/Omron Protocols Support
T100M+ Variables
Timer
1 to 64
Present Values
OMRON
IR128 to IR191
MODBUS
40129 to 40192
Counter
1 to 64
Present Values
IR256 to IR319
40257 to 40320
Clock
TIME[1]
TIME[2]
TIME[3]
IR512
IR513
IR514
40513
40514
40515
Date
DATE[1]
DATE[2]
DATE[3]
DATE[4]
IR516
IR517
IR518
IR519
40517
40518
40519
40520
Data Memory
DM[1]
DM[2]
….
DM[4000]
DM[1]
DM[2]
….
DM[4000]
41001
41002
….
45000
5.2 MODBUS RTU Protocol Support
The new Rev D of the T100MD+ or T100MX+ PLCs also supports the
MODBUS RTU protocol. The difference between the ASCII and RTU
protocols is that the latter transmits binary data directly instead of
converting one byte of binary data into two ASCII characters. A
message frame is determined by the silent interval of 3.5 character
times between characters received at the COMM port. Other than that,
the function codes and memory mappings are identical to the
MODBUS ASCII protocol. Table 5.1 therefore applies to MODBUS RTU
protocol as well.
MOBBUS RTU has following command and response format:
Start
Silence of 3.5
char times
Address
1 byte
Function
1 byte
Data
# byte
CRC 16
2 bytes
END
Silence of 3.5
char times
The following Function Codes are supported:
02
03
05
06
16
Read Input Status
Read Holding Registers
Force Single Coil. Coil #1 = 40001.1, Coil #2 =
40001.2 …. Coil # 17 = 40002.1 and so on.
Preset Single Register
Preset Multiple Registers
5-3
T100MD+ & MX+ PLC
Chapter 5 : Modbus/Omron Protocols Support
5.3 OMRON Host Link Command Support
Command Type
a)
b)
c)
d)
e)
TEST
STATUS READ
ERROR Read
IR Area READ
HR, AR, LR Area
& TC Status READ
f) DM AREA READ
g) PV READ
h) Status Write
l) IR Area WRITE
j) HR, AR, LR Area
& TC Status WRITE
k) DM Area WRITE
l) FORCED SET
m) Registered I/O Read
for Channel or Bit
Header
Level of Support
TS
MS
MF
RR
RH
Full support
Full support
Dummy (always good)
Full support (0000 to 1000)
Dummy (always returns “0000”)
RD
RC
SC
WR
WH, WJ,
WL, WG
WD
KSCIO
KRCIO
QQMR/
QQIR
Full support
Dummy (always returns “0000”)
Dummy (always OK)
Full Support
Dummy (always OK)
Full Support (from DM0001-DM4000)
Full Support for IR Area only
Dummy for other areas.
Full Support for IR and DM only
Dummy for other areas (always 0000)
For detailed description of the command and response formats for
each OMRON Host Link Commands, please refer to C20H/C28H/C40H
PLC Operation manual published by OMRON Corporation.
5.4 Application Example: Interfacing to SCADA Software
SCADA software or MMI systems (also known as LCD Touch Panels)
normally use object-oriented programming method. Graphical objects
such as switches indicator lights or meters, etc., are picked from the
library and then assigned to a certain I/O or internal data address of the
PLC. When designing a SCADA system, first you need to define the PLC
type. You can choose the MODBUS ASCII, MODBUS RTU or OMRON
C20H. Once a graphical object has been created, you will need to
edit its connection and at this point you will be presented with a
selection table that correspond to the memory map of that PLC type.
Example 1: To connect an indicator lamp to Input #9 of the PLC.
You will need to program the switch to connect to IR00.8 for OMRON
protocol. However, If you have defined the PLC as MODBUS type then
this indicator lamp should be connected to address 40001.9. (See
Table 5.1). In either case there is no need to learn about the actual
command format of the protocol itself, as the SCADA software will
automatically generate the required commands to access the input
address that has been chosen for the object.
Example 2: To display reading from ADC #3 as a bar graph on SCADA.
5-4
T100MD+ & MX+ PLC
Chapter 5 : Modbus/Omron Protocols Support
Since the data from ADC #3 is not directly mapped to MODBUS or
OMRON in Table 5.1, you need to add a statement in the custom
function that reads the ADC #3 and copy it into a data memory, e.g.,
DM[100] = ADC(3)
Now you can program the bar graph on the SCADA screen to be
connected to DM[100] if you use OMRON protocol. For MODBUS
protocol the object should be connected to the address: 41100 as can
be seen from Table 5.1.
5.5 Using The T100M+ PLC as MODBUS Master
The T100M+ PLCs supports for MODBUS protocol goes beyond being a
MODBUS slave only. You can use the TBASIC READMOBUS and
WRITEMODBUS commands to send out MODBUS ASCII commands to
access any other T100M+ PLC or any third party MODBUS slave
devices.
Note that when using READMODBUS or WRITEMODBUS command, the
40001 address stated in Table 5.1 should be interpreted as address
0000, and 40002 as address 0001 …. 41001 as address 1000, etc. This
is in accordance with the specifications stated in MODBUS protocols.
MODICON defined zero offset address for the MODBUS command, yet
in their I/O definition the I/O channels are supposed to start from
address 40001. Hence the unusual correspondence. But to maintain
compatibility with the MODBUS specifications we have to adhere to their
definitions.
M+ PLC As MODBUS RTU Master
The new Rev. D T100M+ PLC can also act as a MODBUS RTU master!
The same READMODBUS and WRITEMOBUS commands can be used to
send and receive MODBUS RTU commands. What you need to do is to
add 10 (decimal) to the COMM port number to signal to the processor
that you wish to use MODBUS RTU instead of ASCII to talk to the slaves.
I.e. you should specify port #11 to use RTU commands on COMM1,
and specify port #13 to use RTU commands on COMM3. E.g. the
statement DM[10] = READMODBUS (13, 8, 16) will access via COMM3
the slave with ID = 08 and read the content of register #16. This register
corresponds to MODICON address 40017 and is the OUTPUT[1] of the
slave PLC.
The ability to speak MODBUS RTU greatly extend the type of peripherals
which can be used with a T100M+ PLC. You can now make use of
many off-the-shelf, third party RTU devices to extend the PLC
capability, making the M-series truly super PLCs!
5-5